SECTION XVII_Disease in captive wild mammals and birds

THE COMMUNICABLE DISEASES—PART I

TUBERCULOSIS.

Nearly all infectious diseases have either a limited natural zoological

distribution or are encountered chiefly in one order or division. Thus

typhoid fever is peculiar to man, hog cholera to swine, foot-and-mouth

disease to cows. A second group, including for example anthrax, variola,

hemorrhagic septicemia and malignant edema, is somewhat less specific,

and may occur in several varieties. There is no more widespread,

important infection, zoologically, economically and hygienically, than

tuberculosis, and it would seem that all kinds of vertebrates are

subject to it. Its manifestations too, are sufficiently similar to

support the idea that there must have been originally a common ancestor

of the viruses which we now designate separately by a term to indicate

their immediate source (human, avian, etc.), and moreover it has been

shown that any of the artificially separated varieties or subspecies may

under certain circumstances infect all zoological families.

There is, however, a varying resistance to the tubercle bacillus,

certain zoological groups standing out preëminently as more or less

susceptible to it. There is also a tendency for each animal group to

present features more or less peculiar to itself, but nevertheless the

characteristics, both gross and minute, of the disease caused by the

_Bacillus tuberculosis_ are sufficiently similar to permit close analogy

and to establish a diagnosis when the bacteria are found.

The data collected at this Garden are well suited to elucidate the

susceptibility of wild animals under captive conditions and to

illustrate the nature of lesions in them. Perhaps they do not offer a

perfect cross section of zoological distribution of tuberculosis because

of the predominance in the display of birds, of monkeys and of

ungulates, but the figures will be found significant in certain

respects. Such records cannot be compared with those obtained for

domesticated animals in farms or breeding places, nor can our material

be used to show the incidence for individual species, such as cows, dogs

and the like, in a manner commonly used in veterinary literature. Those

who are interested in this phase of the problem can find in Lubarsch-

Ostertag’s _Ergebnisse_, 1917–18, No. 2, a summary by Eber of all recent

literature, covering nearly 1,700 references, which really amounts to a

review of all modern knowledge of tuberculosis in the lower animals. The

article does not, however, attempt to compare or contrast the incidence

per order or family in wild varieties since little information is

available on these points. There are no reliable data concerning the

existence of tuberculosis in the wild. It is noted in the report of the

British Tuberculosis Commission that monkeys were received with this

disease; Eber mentions that wild swine from a private preserve presented

undoubted evidence of tuberculosis and another similar experience with

pheasants, but these and other citations can give no proper estimate of

exact conditions nor allow a decision that the infection exists at all

under natural environment for in all cases the association with human

beings or domesticated animals cannot be excluded. Tuberculosis is

usually described as a disease of civilization and its incidence surely

varies directly with crowding.

THE TABLE.

Description of Table 23. The study of our autopsy records was begun by

the preparation of the accompanying table, which is based first upon the

zoological classification per order with subdivisions for families where

there are sufficient examples within important orders, and second, upon

percentage of total cases. For the analysis of the pathological types,

headings of probable origin, gross anatomical lesions and visceral

distribution were then made. The first vertical column shows the total

autopsies per order, and where families are given, for each of them. In

three instances Primates, Ungulata and Galli, not all families are

represented, so that the total for the order is greater than that for

the subdivisions quoted. It is noteworthy that we have had no

tuberculosis among nine families of ungulates; this will be discussed

later. The second column gives the total cases of tuberculosis for the

order and family, respectively, followed by a third line of percentages.

For the analysis of the pathology in these animals all the protocols

were reviewed. Forty-eight of them being found unsuitable, deductions

were made according to the natural group, thereby leaving the number

shown in the fifth column for separation according to origin and type.

Analyses in the succeeding columns are made upon number of cases and not

upon percentages, because of the confusion arising from small decimals.

The actual relationships will be pointed out in the notes. Percentage is

not so necessary because comparisons and contrasts are usually made with

classes or orders where the figures are comparable.

TABLE 23.

_Analytical Table Showing Incidence of Tuberculosis per Order and for

Some of the Principal Families, to Which are Added Columns Showing

Probable Origin of Infection, Pathological Type of the Disease and the

Visceral Distribution of the Morbid Process._

════════════════════╤═════════╤════════════╤══════════╤════════════

Order Family │ No. of │ Cases of │Percentage│ Cases not

│autopsies│Tuberculosis│ │sufficiently

│for order│ │ │ described

│or family│ │ │for analysis

────────────────────┼─────────┼────────────┼──────────┼────────────

„ „ │ „ │ „ │ „ │ „

│ │ │ │

Primates │ 498│ 192│ 38.5│ 8

Simiadæ │ 7│ 3│ 43.│ 0

Cercopithecidæ│ 353│ 171│ 48.4│ 8

Cebidæ │ 106│ 18│ 16.9│ 0

Lemures, Lemuridæ │ 86│ 23│ 26.7│ 3

Carnivora │ 481│ 17│ 3.5│ 4

Rodentia │ 199│ 5│ 2.5│ 0

Ungulata │ 365│ 35│ 9.6│ 2

Equidæ │ 11│ 1│ 9.│ 0

Bovidæ │ 123│ 12│ 9.7│ 1

Cervidæ │ 171│ 19│ 11.1│ 1

Camelidæ │ 25│ 3│ 12.│ 0

Proboscidea │ 3│ 2│ 66.│ 0

Totals for Mammalia │ [97]1860│ [97]274│ [97]14.7│ 17

Passeres │ 1355│ 18│ 1.3│ 6

Picariæ │ 87│ 11│ 13.│ 0

Psittaci │ 698│ 38│ 5.4│ 3

Loriidæ │ 24│ 3│ 12.5│ 0

Cacatuidæ │ 80│ 7│ 8.7│ 1

Psittacidæ │ 585│ 28│ 4.8│ 2

Striges │ 133│ 6│ 4.5│ 3

Accipitres │ 196│ 11│ 5.6│ 1

Columbæ, Columbidæ │ 157│ 50│ 32.│ 5

Galli │ 299│ 42│ 14.│ 5

Phasianidæ │ 252│ 22│ 8.3│ 3

Cracidæ │ 38│ 17│ 44.│ 1

Megapodidæ │ 5│ 3│ 60.│ 1

Fulicariæ │ 35│ 9│ _27._│ 0

Hemipodii │ 2│ 1│ _50._│ 0

Alectorides │ 37│ 10│ _27._│ 2

Odontoglossæ │ 6│ 2│ _33._│ 1

Anseres │ 317│ 16│ 5.│ 5

Struthiones │ 32│ 3│ _9.4_│ 0

Crypturi │ 5│ 2│ _40._│ 0

Totals for Aves │ [97]3505│ [97]219│ [97]6.2│ 31

Grand Totals │ [98]5365│ [98]493│ [98]9.1│ 48

────────────────────┴─────────┴────────────┴──────────┴────────────

════════════════════╤════════╤══════════════════════╤═══════════════

Order Family │Net no. │ Probable origin │Pathological Type

│of cases│ │

│ in │ │

│analysis│ │

────────────────────┼────────┼──────────┬───────────┼───────┬───────

„ „ │ „ │Pulmonary-│Intestinal-│ Acute │Massive

│ │aerogenic │ lymphatic │Miliary│caseous

│ │ │ │ │

────────────────────┼────────┼──────────┼───────────┼───────┼───────

Primates │ 184│ 86│ 98│ 3│ 52

Simiadæ │ 3│ 3│ │ │ 2

Cercopithecidæ│ 163│ 76│ 87│ 2│ 46

Cebidæ │ 18│ 7│ 11│ 1│ 3

Lemures, Lemuridæ │ 20│ 6│ 14│ │ 5

Carnivora │ 13│ 6│ 7│ │ 1

Rodentia │ 5│ 3│ 2│ │ 3

Ungulata │ 33│ 27│ 6│ │ 6

Equidæ │ 1│ │ 1│ │ 1

Bovidæ │ 11│ 10│ 1│ │ 1

Cervidæ │ 18│ 14│ 4│ │ 4

Camelidæ │ 3│ 3│ │ │

Proboscidea │ 2│ 2│ │ │

Totals for Mammalia │ 257│ 130│ 127│ 3│ 67

Passeres │ 12│ 9│ 3│ │ 5

Picariæ │ 11│ 1│ 10│ │ 2

Psittaci │ 35│ 13│ 22│ 1│ 9

Loriidæ │ 3│ 1│ 2│ │ 1

Cacatuidæ │ 6│ 4│ 2│ │ 1

Psittacidæ │ 26│ 8│ 18│ 1│ 7

Striges │ 3│ 3│ │ │ 1

Accipitres │ 10│ 5│ 5│ │ 2

Columbæ, Columbidæ │ 45│ 10│ 35│ │ 12

Galli │ 37│ 10│ 27│ │ 12

Phasianidæ │ 19│ 2│ 17│ │ 4

Cracidæ │ 16│ 7│ 9│ │ 7

Megapodidæ │ 2│ 1│ 1│ │ 1

Fulicariæ │ 9│ 1│ 8│ │ 1

Hemipodii │ 1│ 1│ │ │ 1

Alectorides │ 8│ │ 8│ │ 2

Odontoglossæ │ 1│ │ 1│ │

Anseres │ 11│ 2│ 9│ │ 4

Struthiones │ 3│ 3│ │ │

Crypturi │ 2│ │ 2│ │

Totals for Aves │ [99]188│ 58│ 130│ 1│ 51

Grand Totals │ [99]445│ 188│ 257│ 4│ 118

────────────────────┴────────┴──────────┴───────────┴───────┴───────

════════════════════╤════════════════════════╤════════════════════════

Order Family │ Pathological Type │ Visceral Distribution

│ │

────────────────────┼───────┬──────────┬─────┼─────┬─────┬──────┬─────

„ „ │Nodular│ Chronic │Pearl│Lungs│Liver│Spleen│Lymph

│caseous│ fibrous │type │ │ │ │nodes

│ │ and │ │ │ │ │

│ │ulcerative│ │ │ │ │

────────────────────┼───────┼──────────┼─────┼─────┼─────┼──────┼─────

Primates │ 108│ 16│ 5│ 173│ 122│ 149│ 145

Simiadæ │ │ │ │ 3│ 2│ 3│ 3

Cercopithecidæ│ 96│ 16│ 3│ 156│ 111│ 136│ 128

Cebidæ │ 12│ │ 2│ 14│ 9│ 10│ 14

Lemures, Lemuridæ │ 15│ │ │ 17│ 14│ 17│ 12

Carnivora │ 8│ 4│ │ 11│ 4│ 2│ 6

Rodentia │ 2│ │ │ 4│ 2│ 2│ 4

Ungulata │ 1│ 24│ 2│ 28│ 7│ 3│ 25

Equidæ │ │ │ │ │ │ │ 1

Bovidæ │ 1│ 9│ │ 9│ 4│ 2│ 7

Cervidæ │ │ 13│ 1│ 17│ 2│ │ 14

Camelidæ │ │ 2│ 1│ 2│ 1│ 1│ 3

Proboscidea │ │ 2│ │ 2│ │ │

Totals for Mammalia │ 134│ 46│ 7│ 235│ 149│ 173│ 192

Passeres │ 7│ │ │ 9│ 5│ 5│

Picariæ │ 8│ │ 1│ 2│ 9│ 6│ 1

Psittaci │ 25│ │ │ 18│ 24│ 14│ 2

Loriidæ │ 2│ │ │ 3│ 3│ 1│

Cacatuidæ │ 5│ │ │ 5│ 5│ 2│

Psittacidæ │ 18│ │ │ 10│ 16│ 11│ 2

Striges │ 2│ │ │ 3│ 3│ 2│

Accipitres │ 7│ 1│ │ 8│ 6│ 8│ 1

Columbæ, Columbidæ │ 33│ │ │ 24│ 40│ 34│ 1

Galli │ 24│ 1│ │ 20│ 34│ 29│ 2

Phasianidæ │ 15│ │ │ 7│ 18│ 15│ 1

Cracidæ │ 8│ 1│ │ 12│ 15│ 13│

Megapodidæ │ 1│ │ │ 1│ 1│ 1│ 1

Fulicariæ │ 8│ │ │ 4│ 8│ 8│ 1

Hemipodii │ │ │ │ 1│ 1│ 1│

Alectorides │ 6│ │ │ 4│ 8│ 7│ 2

Odontoglossæ │ 1│ │ │ │ 1│ 1│

Anseres │ 5│ 2│ │ 4│ 7│ 8│ 1

Struthiones │ │ 3│ │ 3│ 2│ 3│ 2

Crypturi │ 2│ │ │ 1│ 2│ 2│

Totals for Aves │ 128│ 7│ 1│ 101│ 151│ 128│ 13

Grand Totals │ 262│ 53│ 8│ 336│ 300│ 301│ 205

────────────────────┴───────┴──────────┴─────┴─────┴─────┴──────┴─────

════════════════════╤══════════════════════════════════════════════════════

Order Family │ Visceral Distribution

│

────────────────────┼─────────┬──────┬─────────┬──────┬─────┬─────┬────────

„ „ │Intestine│Kidney│ Serous │Bones │Brain│Heart│Pancreas

│ │ │membranes│ and │ │ │

│ │ │ │joints│ │ │

│ │ │ │ │ │ │

────────────────────┼─────────┼──────┼─────────┼──────┼─────┼─────┼────────

Primates │ 30│ 84│ 70│ 2│ 2│ 7│ 3

Simiadæ │ 2│ 1│ 1│ │ │ │

Cercopithecidæ│ 24│ 76│ 63│ 2│ 2│ 7│ 2

Cebidæ │ 4│ 7│ 6│ │ │ │ 1

Lemures, Lemuridæ │ 2│ 7│ 1│ │ │ │ 1

Carnivora │ 1│ 4│ 3│ 1│ │ │

Rodentia │ 1│ 2│ 2│ 1│ │ │

Ungulata │ 1│ 2│ 7│ │ │ │

Equidæ │ │ │ │ │ │ │

Bovidæ │ 1│ 1│ 1│ │ │ │

Cervidæ │ │ │ 5│ │ │ │

Camelidæ │ │ 1│ 1│ │ │ │

Proboscidea │ │ │ │ │ │ │

Totals for Mammalia │ 35│ 99│ 83│ 4│ 2│ 7│ 4

Passeres │ 4│ │ 4│ │ │ │

Picariæ │ 4│ 1│ 3│ 1│ │ │

Psittaci │ 12│ 6│ 6│ │ │ 1│

Loriidæ │ 1│ 1│ 1│ │ │ │

Cacatuidæ │ │ 1│ 1│ │ │ 1│

Psittacidæ │ 11│ 4│ 4│ │ │ │

Striges │ │ │ 3│ │ │ │

Accipitres │ 4│ 3│ 6│ │ │ 2│

Columbæ, Columbidæ │ 16│ 13│ 20│ │ │ 1│

Galli │ 20│ 7│ 15│ │ │ │ 1

Phasianidæ │ 10│ 2│ 6│ │ │ │ 1

Cracidæ │ 10│ 5│ 7│ │ │ │

Megapodidæ │ │ │ 2│ │ │ │

Fulicariæ │ 3│ 3│ 4│ │ │ │

Hemipodii │ 1│ 1│ 1│ │ │ │

Alectorides │ 3│ 3│ 7│ │ │ │

Odontoglossæ │ 1│ │ │ │ │ │

Anseres │ 3│ 4│ 4│ │ │ │

Struthiones │ │ 1│ 1│ │ │ │

Crypturi │ 2│ 1│ │ │ │ │

Totals for Aves │ 73│ 43│ 74│ 1│ 0│ 4│ 1

Grand Totals │ 108│ 142│ 157│ 5│ 2│ 11│ 4

────────────────────┴─────────┴──────┴─────────┴──────┴─────┴─────┴────────

See page 484, for description of tabulation.

For meaning of italics see foot note Table 1.

These and figures set opposite them are cases not percentages.

It is generally conceded that the principal and only significant routes

of origin for tuberculosis are via the respiratory and alimentary

tracts. The criteria upon which to decide the route that has been

followed are by no means definite and may not be for any given case

unexceptionable. In birds the alimentary tract is conceded to be the

important one, while in mammals an aerogenic route is believed to be the

rule. However, since feeding experiments have shown that tubercle

bacilli can gain the lungs by passing through the intestinal wall and

abdominal lymphatics without leaving gross traces, the decision that one

or the other route has been taken may be erroneous, and statistics

therefore can often be fallacious. It is usually the rule to assume that

the oldest or best developed lesions occur where the originally settled

organisms exerted their maximum effect. The questions of infection-path

and of original lesion not having been settled it is obvious that

decision as to the route must be in the nature of an estimate. With

these limitations in mind I have divided the cases into probable

respiratory and alimentary origins according to the following criteria.

Where the lesions were wholly respiratory or within the lymph glands of

the trachea and bronchi the decision was not so difficult. Predominance

of the pulmonary disease with recent lesions in other organs was taken

to indicate an aerogenic origin. The chronic ulcerative or fibrous

pulmonary lesions were also ascribed to those beginning in the lungs.

The alimentary tract was considered for this purpose as beginning in the

tonsillar area and ending at the anus. This is as I understand the

customary teaching. When the lymph nodes of the alimentary area were

advanced in the process, the intestinal method was held responsible. It

is of course not to be forgotten that organisms coughed up from the

lungs and swallowed may be responsible for lesions within the alimentary

system. However, a predominance of intestinal, splenic, hepatic and

lymphatic lesions caused me to place the case with those originating

from the alimentary tract. Granting the limitations of our knowledge, of

the criteria and of my own judgment, it is noteworthy that the results

of this division of the table are not contradictory to the usual

teaching, the most conspicuous being the predominance of the alimentary

infection of Aves and in the order Primates, whereas the pulmonary route

has the highest figures for the Ungulata.

The next subdivision of the table concerns the gross pathological type.

Beginning with the most acute form, the acute miliary, progression is

made in terms of chronicity—then following in order the massive caseous

form including caseous pneumonia, the caseous miliary or nodular form so

well represented by the monkey, then the fibroulcerative type such as

one encounters in human consumption, including also forms in which

fibrosis predominates, and lastly the rather uncommon pearl disease.

This classification has been relatively easy to follow and can be

readily imagined by the reader. There are of course intermediate cases

or transition forms and there have been instances partaking of more than

one character. The groupings present only gross appearances and, with

few exceptions, are not to be taken as direct indications of type

incidence in special groups.

Visceral distribution is shown in the last gross section of the table;

single cases or unusual locations are not tabulated but will be

separately discussed. The visceral distribution is made upon evident

gross lesions or their discovery in organs whose condition suggested the

need of microscopic study for confirmation. The figures in the table

will be reviewed first upon the incidence as a whole and then between

classes and orders. This will be succeeded by an analysis of the

particulars for each order and then for each of the pathological

headings.

TOTAL AND CLASS INCIDENCE.

The autopsies upon 5,365 animals have revealed the existence of

tuberculosis in 492, a percentage of 9.1. This means that lesions due to

the _Bacillus tuberculosis_ were present, but they were not always the

cause of death, since many specimens have been executed and others have

had sufficient pathology to kill, aside from the tuberculous changes.

Deaths due to the disease alone are difficult to estimate, but seem to

be about 325 or 6 per cent. These figures, while they represent the

total incidence, lose considerably in significance when the factors are

analyzed. Mammalian incidence is 14.7 per cent., Avian 6.2 per cent.,

but the former is based upon figures obtained from six of twelve orders

numbering 1,860 animals, whereas the latter represent the cases in

fourteen of twenty orders numbering 3,505 birds. The percentages are

considerably increased by high figures for a few orders, Primates,

Lemures, Columbæ for examples. There are missing from the list very few

orders of which we have any notable number of autopsies, Marsupialia and

Herodiones being the only important ones; it would seem that these

orders have a high resistance to the disease.

Investigation into the origin of the disease in mammals and birds shows

with definiteness the preponderance of the alimentary route influence in

the latter, but for the former the figures cannot be said to be

conclusive. The bird excretes large numbers of bacilli with the feces

thereby soiling the feed and the ground. This is due to the frequency of

intestinal open lesions and to the really enormous numbers of bacilli

which are in the morbid tissue. I think it can be said with safety that,

other things being equal, the bird excretes bacilli constantly and in

greater numbers than does the mammal, and that in physically comparable

lesions there are more bacilli in the avian than in the mammalian.

The inconclusive figures for the origin of the disease in the mammal can

be clarified very little by the subtraction from the tables of the

figures for the very susceptible Primates. By doing this it would seem

that the respiratory route dominates as 43 to 29, whereas if the

reasonably susceptible Lemures be also deducted the ratio becomes as 38

to 15. It would seem that the evidence favors the aerogenic route in the

mammal.

PATHOLOGICAL TYPES.

An inquiry into the gross pathological types reveals at once the

frequency with which the nodular and massive caseous forms appear. If

the number of cases be reduced to percentage it will be found that 59

per cent. of all specimens presented the nodular variety and 26.6 per

cent. the massive caseous form. These large figures (equaling when

combined 85 per cent.) coupled with the fact that only 12 per cent. of

the total were fibroulcerative and 1.8 per cent. of the pearl type,

would seem to indicate that the nodular and massive caseous processes

are the lesions to be expected in wild animals. Furthermore, if these

nodular and caseous forms speak for recent infection or acuteness of the

morbid process, it would seem that wild animals have a low tissue

resistance to tuberculosis. It is a widespread belief, in some degree

well supported, that a disease new to an animal species is highly fatal

and that the survival of the race depends upon an active self-

immunization or the survival of the pathologically least susceptible. If

tuberculosis be a disease of civilization, these figures would suggest

that it is absent in nature. As a further support of this idea it can be

said that with the exception of two cases in ungulates, no fibroid

tuberculosis, approaching the quiescent type as seen in man and rarely

in domestic animals, was encountered. Very rarely calcareous deposits

will be found in both simian and ungulate lesions but these need not

indicate a tendency to general healing although at that place the

process may be inactive. The bird uses considerable fibrous tissue in

the construction of its tuberculous mass but fibrosis never masters the

situation with the formation of scar tissue sufficient to wall off the

process. Pearl disease, a fibrocaseous condition, is not a healing

fibroid procedure and is, in our material, of no numerical significance.

VISCERAL DISTRIBUTION.

The distribution of the morbid lesions in the viscera presents some

interesting features. In the first place the data leave no doubt that

the most susceptible tissue in the wild animal body is, as in the case

of human and domestic animals, the lung. The susceptibility of this

organ in the two classes is however a different matter since in the

mammal 91.4 per cent. show pulmonary lesions while only 53.7 per cent.

of birds are so affected. Part of the reason for this appears in the

figures for the principal abdominal organs, of which the liver and

spleen occupy the prominent places. The mammalian livers show 58.2 per

cent., the avian 80.3 per cent.; 67.5 per cent. of mammalian spleens,

68.0 per cent. of avian spleens have tuberculous lesions. The figure for

the mammalian spleen is distorted because of the peculiar susceptibility

of this organ in the monkey, it being conspicuously free of lesions in

most mammalian orders. The intestines presented discernible lesions in

practically 40 per cent. of birds but only in 13.5 per cent. of mammals.

Renal involvement was found in 38.4 per cent. of mammals and 22.9 per

cent. of birds.

A study of the changes in the serous surfaces is complicated by the

difference of anatomy in the two classes. The mammal has separate closed

serous sacs well guarded against invasion from mucous surfaces whereas

in the bird the air sacs and serous cavities are closely related, the

latter being loosely applied to viscera they are intended to cover.

Moreover in Aves direct infection of the air sacs seems a definite

possibility. Notwithstanding the fact that the bird’s sacs and serous

surfaces appear so open to infection there is no great preponderance of

lesions within them—Aves 39.3 per cent. Mammalia 32 per cent. The lymph

nodes were tabulated as a tissue rather than according to location, the

latter method being found profitable for discussion in a few orders

only. As might be expected the abundant lymph nodes of the mammal were

affected out of all proportion to those in the bird. These matters will

be discussed later. The remaining figures on the table have no

comparative value.

ORDINATE CHARACTERISTICS.

The Primates as an order have shown low resistance to tuberculosis, a

fact well known to general observation. How much this is due to the

unsanitary surroundings to which these naturally free active beasts are

subjected, in catching, transporting and storing for sale, must at

present remain conjectural, but they are probably infected with ease as

our experience in this laboratory suggests. Desiring a tuberculous

monkey for certain tuberculin tests, I injected one hundredth of a

milligram of a human culture, known to produce definite lesions in

rabbits; the animal died in three months with advanced general

tuberculosis. The unexpected and interesting feature of our figures is

the susceptibility of different families within the order. The Old World

monkeys, Simiadæ and Cercopithecidæ have a combined incidence two and

one-half times as great as the New World Cebidæ, and the marmosets had

no tuberculosis at all in the thirty-two specimens. Possibly this is a

matter of transportation and handling, which reduces the resistance and

offers chance to infect apes and baboons. The New World capucin monkeys

have their exposure too since many of them are household pets before the

Garden receives them. Their usual life in captivity is however shorter

than that of Old World varieties, they therefore being exposed to

infection for a shorter time. It would seem however that American

Primates are more resistant to the disease than African and

Australasian.

The form of tuberculosis to which this order is liable is well described

in text-books, it being so characteristic that the term “monkey

tuberculosis” is used to distinguish it. The purpose of the term is to

compare the lesions with certain cases of generalized tuberculosis in

children. It is characterized by a nodular involvement of the liver and

of the spleen particularly, sometimes also of the lungs but in fatal

cases the last organ is commonly the seat of massive caseation or

caseous pneumonia. The prominence of the pulmonary lesions often makes a

decision of origin difficult since important changes may be found in the

liver and abdominal nodes. Blair at New York, and Rabinowitsch at Berlin

are of the impression that many cases of monkey tuberculosis start by

pharyngeal and tonsillar infection because they found cervical adenitis

so commonly. Our records and specimens would support this idea in only

fourteen instances and I am of the impression that the lower intestinal

route is more often responsible, even to a higher figure than is

recorded in the table. This view is based upon the frequent occurrence

of enlarged glands in the mesentery, retroperitoneum and posterior

mediastinum, in the latter location being quite as prominent if not more

so than in the bronchial and tracheal area. Occasionally deposits of

calcareous matter will be found in old caseous glands but in such

animals there has always been some other spot of activity of

tuberculosis. The frequency with which the liver and spleen are affected

gives opportunity for hematogenic spread, a method of no small

importance in the opinion of Eber. The chronic ulcerative form is quite

well displayed in monkeys, interestingly enough to cite an illustrative

case at the end of this division of the discussion. Five cases of

distinct chronic cavitation were encountered; several small recent

cavities were found in the massive caseous pneumonic cases. The two

acute miliary cases and one of the pearl type will be discussed briefly

on a later page.

Despite the prominence of the liver, spleen and lymph nodes, the lungs

stand ahead of all others by a safe margin of visceral incidence. The

spleen stands in the third place in this order and in the next, Lemures,

but in no other mammalian group does this organ occupy so prominent a

position. The susceptibility of lymphatic tissue in the monkey is

further illustrated by the large number of cases showing lesions in

lymph nodes. It is rather striking however that our material showed very

few active ulcerations in the lymphoid plaques of the intestinal wall

nor indeed do the intestines present a large numerical involvement.

Serous membrane tuberculosis is chiefly that of the pleura, upon which

early precaseous tubercles are frequently found, usually in conjunction

with pulmonary disease. Tuberculous peritonitis of the plastic and

nodular variety occurred only six times, though light adhesions to

nodules in the liver and spleen were quite common. Pericarditis was

found five times, in three of which there was myocardial disease; which

of the two was primary was not indicated in the notes but from present

reading it would seem that the heart muscle was involved first.

The next order, Lemures, has a susceptibility of about half that of the

monkeys judging by the percentage incidence. Analytically the members of

this group react quite like the preceding order in having the same types

of origin, pathology and organic distribution. Since they are so close

zoologically, present similar lesions and are tested in the same manner

as the monkeys, we group them together and shall proceed to discuss

special cases of interest in both orders.

Special Cases in Primates and Lemures. Acute general miliary

tuberculosis occurred thrice in Old World and once in New World monkeys.

The first case took its origin in a caseous gland in the bronchotracheal

area, the lung showing a minor degree of involvement with milia but no

older process. The second took its origin in the mesenteric area and the

organs of this section of the body were most affected. The only case in

the Cebidæ seemed to be of intestinal origin since an acute plastic

peritonitis with fluid exudate accompanied the generally miliary

disease.

Pearl disease of the bovine type has been encountered on four occasions

but it cannot be said to have developed to the state of perfection seen

in the cow. There is lacking the masses of nodules growing together in a

fungoid character usually seen on the pleura and peritoneum. The monkey

form is in isolated nodules of gray-yellow color which may show caseous

centres. The visceral lesions are in firm separate areas not tending to

soften or coalesce. Two of these monkeys died from recent pulmonary

exacerbations. From one of the cases a bovine bacillus, judging from

culture and rabbit virulence, was isolated.

As a good example of monkey tuberculosis, illustrating at the same time

a chronic ulcerative pneumonitis with cavitation, the following case is

cited:

Green Monkey (_Cercopithecus callitrichus_) ♀ . Was coughing and

drooping for two days before death. Chronic ulcerative tuberculosis of

lungs with cavity formation; early conglomerate tuberculosis of liver;

conglomerate caseous tuberculosis of spleen; early conglomerate

tuberculosis of ileum (Peyer’s patches); acute catarrhal enteritis;

miliary tuberculosis of right kidney. The animal is well preserved,

sleek, with a moderate amount of fat. The left pleura is largely

obliterated by adhesions in the lower portion. As lung is freed it is

torn, showing a cavity measuring 3 × 3 × 4 cm., which is filled with a

curdy gray material. Cavity has well defined walls. Rest of lower lobe

in which this cavity lies is solidified, red and edematous and

contains numerous conglomerate tubercles. Upper lobe practically free

of tubercles; shows compensatory emphysema. The right lung closely

resembles the left but lacks the cavity. The liver is enlarged, soft

and friable, of red color, spotted yellow. Serous and section surfaces

show closely packed early conglomerate tubercles. The spleen is of

normal size, soft, has red pulp with large conglomerate tubercles

which project slightly on the capsule. The kidneys are apparently

normal except for the presence of two or three subcapsular large,

solitary tubercles in the right organ. The duodenum has thickened

walls, mucosa bright, brilliant scarlet hue. In the ileum the walls

are thickened, mucosa bright red, agminated follicles hyperplastic

elevated and display several (4–12) miliary tubercles. These may be

seen shining through on the serous surface but there is no peritoneal

tuberculosis. No ulceration of Peyer’s patches. Contents of large

intestine is rather dry and here the mucosa shows exaggerated rugæ

which cannot be smoothed out. Walls are thickened, and ulceration,

while suggested, cannot surely be determined.

An interesting case of primary tuberculosis in the larynx detected at

postmortem after a tuberculin injection is as follows:

[Illustration:

FIG. 51.—BOVINE TUBERCULOSIS IN THE MONKEY. THIS SPECIMEN SHOWS THE

BOVINE PEARL DISEASE ON THE COSTAL PLEURA, AND SERVES AS WELL TO

ILLUSTRATE THE NODULAR TUBERCLES COMMONLY FOUND IN THE SPLEEN OF ALL

PRIMATE TUBERCULOSIS.

]

Black and White Lemur (_Lemur varius_) ♂ . Miliary tuberculosis of

larynx; perilaryngitis and retropharyngeal lymphadenitis. Killed

because of unsatisfactory chart after injection of tuberculin. The

only tuberculous lesion to be found in the body, which is in excellent

shape, is in and about the larynx. The lesions within are on the

epiglottis, false and true vocal cords and the main ventricle. On

either side of the root of the epiglottis, there are a few recent

tubercles. The lesion in the retropharyngeal lymphatics is recent and

diffuse. This is probably primary as it is not known that the

retropharyngeal glands drain to or from the larynx. About the lesions

on the laryngeal mucosa there is an area of congestion probably due to

the tuberculin injection.

Local lymphatic tuberculosis of comparative interest was encountered a

few times. Three cases of cervical adenitis, large enough to be visible,

were seen, of which one broke down about two weeks before death, and

discharged. The others did not ulcerate through the skin but, contrary

to the usual rule for the human being, remained as isolated glands only

lightly adherent to one another where they lay adjacent. There was also

seen an ulcerating tuberculous lymph node in the groin of one monkey,

the animal having rather pronounced abdominal and pelvic tuberculosis.

Two instances of tonsillar tuberculosis are recorded, in both of which

the lesion was of some duration and associated with caseation in the

lymph node lying immediately behind and below it. A Guinea Baboon

(_Papio sphinx_) had as an unusual part of his general tuberculosis, an

active caseopurulent collection in the antrum of Highmore, which

attacked the upper maxilla and immediately adjacent muscle; tubercle

bacilli could be demonstrated.

One of the cases of nodular or massive peritoneal tuberculosis is quite

like the tumor-forming variety of human adolescents; it is as follows:

Reddish Macaque (_Macacus rufescens_). Caseous tuberculosis of

mesentery and spleen; miliary tuberculosis of lungs, pleura and liver;

chronic myocarditis. The lymphatic glands of the posterior and

superior mediastinum and bronchi are slightly enlarged, soft and

anthracotic but do not show any tuberculous change. Both lungs are

riddled with small, firm, gray miliary tubercles, some surrounded by a

clear mantle of connective tissue. The intervening lung is practically

normal. Pleura over base of right lung on both surfaces shows small,

pale miliary tubercles. The liver contains various sized miliary

tubercles. There is a large caseous mass in posterior end of spleen

with adhesions to kidney, stomach and colon. Retroperitoneal glands

are much enlarged, firm, homogeneous—probably tuberculosis of a

different type. Lesser omentum contains one caseous gland. Few caseous

glands in great omentum. In the right iliac region there is a large

mass involving many coils of intestine. It is found to arise probably

from the ileocecal glands and can be traced along the mesentery to the

central lymphatic stalk. The mass involved the tissues of the

mesentery and surrounds many coils of intestine. Cecum and first part

of colon can be traced over its right side. Rectum is free except on

right side where it is lightly attached to the mass. Epicardium is

gray and irregularly thickened and the muscle just beneath serous

membrane is pale and streaked with red lines.

There have been three cases of tuberculosis of the internal male genital

area, one of which was suspected of having been the primary seat of the

disease; it was described on page 315. The other two could have been

secondary since other points of morbid change were as old or older. One

of these cases formed a tumor as large as a goose egg at the vesical

neck, obstructing the flow of urine and blocking up the seminal vesical,

in consequence of which paralytic distention occurred in the bladder

while the vesicles were tightly filled with inspissated semen. A case of

Fallopian salpingitis has also been cited. Two instances of cerebral

tuberculomata have already been described.

Carnivora. This order has the reputation of being quite resistant to the

tubercle bacillus, based upon the relative infrequency among cats and

dogs in contrast to cows and swine. Some veterinary statistics cite the

incidence up to 5 per cent., and occasional references may be found to

tuberculosis in circus lions and tigers. Our records would suggest that

in gardens the wild varieties of this order have about as much of the

infection as the domestic carnivores, 3.5 per cent. The group is made of

six Felidæ, one Viverridæ, three Canidæ, six Procyonidæ, and one Ursidæ.

The first family includes a lion, tiger, a jaguar and three smaller

cats. The Canidæ are all small foxes. The Procyonidæ are all coatis. The

features of this order are the occurrence of the fibroulcerative variety

with cavitation in the Felidæ and the caseous nodular abdominal and

glandular disease in the coatis. All these animals, even those of the

last named variety and pathological type, tend to show some tissue

resistance to the tuberculous disease. Connective tissue activity is

characteristic of the process, considerable distortion being produced by

the fibrosis. This feature is borne out where the tissues are studied

microscopically. Definite milia are sometimes found, but they consist of

epithelioid and round cells with imperfect caseation, giant cells being

often missing. About the miliary tubercles a diffuse and not essentially

specific tuberculous granulation tissue is found, mixed with which is

much connective tissue growth. The fibrotic adhesion-forming serous

membrane tuberculosis of carnivores seems worthy of emphasis by the

citing of a case in point. White nosed coati (_Nasua narica_), was

received in poor condition and died in a few days. Upon dissection a

slightly turbid yellowish fluid was found to occupy what remained of the

peritoneal cavity which was reduced in size by dense adhesions of the

intestines into an inflammatory mass. The omentum was a diffuse

thickened apron, also beset with fine tubercles, lying over the mass.

Fine young tubercles could also be found upon the intestines and liver

while the mesenteric lymph nodes were early in caseation; thoracic

organs not infected.

One of the most interesting cases concerned hypertrophic osteitis in a

chronically tuberculous lion; the feet are discussed on page 346. This

process was described by Marie for human beings many years ago, and was

reported in dogs by Cadiot[100] in 1912. This beast was one of five

large cats which have died from tuberculosis in its chronic ulcerative

form. Three of the cats, one fox and the bear showed definite

cavitations of a ragged loculated form. The cavities were usually of the

multiple variety and were found in the posterior, that is lower lobe.

Rodentia. The paucity of cases in this order permits little information

to be drawn from the form of tuberculosis. The total seems to have been

swollen by a group of three beavers, all of which came in one shipment.

The remainder were a Capybara and an Agouti. The general type is that of

much caseation with little or no surrounding fibrosis. One illustrative

case is cited:

American Beaver (_Castor canadensis_). General tuberculosis. The

animal presents generalized tuberculosis. The regional lymph nodes

show caseous nodules. The right hip joint shows caseous material about

the acetabulum with necrosis and pathological fractures in the os

innominatum immediately above the acetabulum and including its cavity.

Lungs show almost no normal respiratory tissue, the process being a

diffuse precaseous, partly gelatinous pneumonic phthisis. The superior

and posterior mediastina show caseous glands. There is miliary

tuberculosis of the liver. Nodular caseous tuberculosis of the spleen

with small tubercles and some cirrhosis of the intervening tissue.

There are caseous nodules in all perirenal glands and in the kidney

cortices. The psoas muscle glands are densely caseous. The pelvic

organs except about the right acetabulum escape involvement. Adrenals

not opened but probably not involved.

Ungulata. This order shows the most definite figures among those for the

order of mammals. Nearly one-tenth of the whole number of specimens have

had some form of tuberculosis and of a very definite character. It is

well at first to mention, however, that only four of thirteen families

are represented, from which four came 328 of the total 365 autopsies.

The remaining thirty-seven were such animals as tapirs, giraffes, swine,

and peccaries, in all of which tuberculosis has been reported from

elsewhere.

Pulmonary disease with less prominent lesions in other organs,

especially the intestines and their related glands, speaks in favor of

the aerogenic route being the common one. This of course has been a bone

of contention among veterinarians, and I do not presume to settle the

matter with these figures.

This order resists tuberculosis to a certain degree as attested by the

fibroulcerative character of the majority of the cases. Two instances,

one in a buffalo and one in a deer, showed very highly fibrotic

pulmonary lesions with a partial attempt to surround and wall off

numerous areas of caseation. So too in this order there is a greater

tendency to calcification, both in the intra- and extrapulmonary nodes.

It is to be emphasized that in our material the thoracic lymph nodes are

affected more than the abdominal and regional as 3 to 1. The apparent

immunity of the spleen of this order is well illustrated.

The paucity of serous surface involvements in the wild Bovidæ and their

prominence in the Cervidæ cannot be ignored in the figures, but it seems

misleading since pleural growths and adhesions are quite common in the

domestic Bovidæ. The case in the Equidæ was that of a Zebra with a large

tuberculous abscess in the retroperitoneal glands forming a tumor in the

left renal region. It was quite well surrounded by fibrosis, and the

infection had not extended; it seemed quite recent. Analysis of the

figures for the remaining three families of ungulates offers little for

contrast and much for comparison; it is the usual picture as seen in the

domestic cow. Some special cases are worthy of review.

An interesting specimen of softened glands chiefly on one side of the

neck was found in a Fallow deer (_Cervus dama_). It resembled the

juvenile human cases that require surgical attention. Although palpable

lymph nodes can be found in practically all cases of generalized

tuberculosis in the Ungulata, this is the only case in our records in

which they have presented a large tumefaction and broken down. Pulmonary

cavitation is recorded but thrice, one for each of the last three

families. Fibrocaseous tuberculosis of the testes was discovered in a

Nylghaie (_Boselaphus tragocamelus_), but there is no knowledge of

mating or offspring. An ischiorectal abscess was found in an American

Bison (_Bison bison_) showing nodular precaseous tubercles of the lung.

The former was the cause of death. No tubercle bacilli could be found in

the abscess contents, so that the tuberculous basis is inferred, not

proven. Tuberculous salpingitis in a Nylghaie was discussed on page 306.

Proboscidea. Eber mentions in the article already referred to that there

are three reports in the literature of tuberculosis in elephants. When

looking for an explanation of tuberculosis in this animal it must be

remembered that it is one of the most attractive objects in a zoological

garden and receives perhaps more attention, including feeding, from

visitors than any other specimen. The beast while possessing some tissue

resistance to tuberculosis, is by no means immune thereto, as has been

thought by some persons on account of its reputed longevity, and

therefore he is to be protected from infection just as much as other

animals. It would appear that he may present caseous pneumonia or

nodular caseous disseminated lesions. Our two cases, in animals at the

Garden twenty and thirty-eight years respectively, were both of the

fibrocaseous variety; the lesion was confined to the lungs. A brief

description of their lesions is as follows:

Indian Elephant (_Elephas indicus_) ♂ . Chronic polyarthritis. Chronic

myocarditis. Chronic hepatitis (cirrhosis). Parenchymatous nephritis.

Chronic tuberculosis of the lungs, partly encapsulated. Pigmentation

of the spleen. The pleuræ are very fat but the surfaces are smooth and

devoid of adhesions. The lymph nodes of the mediastinum are about

10 × 20 cm. for the largest while the smaller ones vary around 2 × 4

cm. They are firm, deep red-brown without clear divisions into medulla

and follicular cortex. There are several large, firm, pale rather

cheesy follicles in all the large ones and a few of the small. These

do not appear like tuberculosis. The lungs are flaccid and soft; gray

and red mottled. The bronchi are firm and stand open. Around one in

the upper lobe of the right lung, there is a large area of cheesy

degeneration around which a zone of connective tissue has formed. This

extends about the bronchus about halfway in a sheath-like manner.

There is also a separate nodule the size of a cherry with a cheesy

centre. The trachea appears normal. Tubercle bacilli could be

demonstrated in the cheesy material. Microscopic section of lung

around the cheesy area shows a low grade chronic granulation tissue in

some places enclosing cheesy masses with giant cells on the margin.

The neighboring septa are slightly thickened and in some places

broken, forming emphysematous cavities. Some of these cavities are

edematous.

Indian Elephant (_Elephas indicus_) ♀ . Miliary and conglomerate

caseous tuberculosis of lung. Edema of lungs. Endarteritis deformans

of lung. Cloudy swelling of liver. Chronic passive congestion of

liver. Hemosiderin pigmentation of liver. Acute parenchymatous

nephritis. Chronic passive congestion of spleen. Chronic hyaline

perisplenitis. Multiple calcified fibroid tumors of uterus. Leiomyoma

of uterine cornu. Senile atrophy of ovaries. Acute catarrhal

enteritis. There are some adhesions of the upper lobes of the lung to

the ribs. The lungs are large, increased in weight, color pink and

mottled red, air content diminished. There are several masses of

tubercles, each as large as a cocoanut, in both lobes. In one such the

tubercles are yellow and caseous; some are fibroid but none are

liquefied or calcified. The fibrous tissue of the lung parenchyma here

is much overgrown. In one instance the terminus of a bronchus is

solidly plugged by caseous material. Mucosa of bronchi is reddened,

markedly ulcerated, ulcers overlaid by mucopus.

INDIVIDUAL FEATURES OF AVIAN TUBERCULOSIS.

The avian form of tuberculosis is somewhat peculiar in its physical

appearance as well as in its distribution. The isolated nodular type is

far and away more common by more than 100 per cent. than all the other

types combined. These nodules are usually well circumscribed, and to the

naked eye suggest that they have a restraining fibroid wall. This is,

however, not the case, the impression being due to the dense but

actively growing fibrocellular cortical zone of the tubercle. The centre

of the nodule, instead of having the soft character like Camembert

cheese, resembles the firm but brittle American dairy cheese. Upon

opening such an area the central necrotic mass may split away from its

cortex and even shell out, leaving a cavity lined by a gray-yellow

membrane. These characters are best displayed in nodules of moderate

size, the small ones being like the yellow mammalian analogue, the large

being like indefinite cheesy masses. In the surrounding tissue evidences

of inflammatory processes seem decidedly greater in our material than I

am accustomed to see in human and veterinary pathology. This, it seems,

should be emphasized since secondary infection with pus cocci and other

pathogenic germs appears less often in birds than in mammals.

The difference speaks, therefore for a difference either in the tubercle

bacillus of birds or the avian physiology. Judging by the limited morbid

processes produced by injecting avian bacilli into rabbits and guinea-

pigs the reaction of the bird itself would not seem wholly responsible

for the difference. The local tissue reaction in all avian lesions is

mononuclear and fibrous, softening and pus being rare. It would seem

from this and similar operations that the bird expresses its resistance

to the bacteria by a fibrocellular reaction which goes on to fibrosis

without softening; perhaps this means also that their polynuclears are

not sufficiently active, but the pathogenic power of the bacillus itself

doubtless is individualistic.

The character of the cheesy degeneration is likewise different from the

mammalian. It seems like an abrupt hyaline necrosis of a large central

mass and not the slower cell death seen in the other types of tubercle.

At times the degenerated area, instead of having the yellowish color of

caseation, will present what we have designated “gelatinous

tuberculosis,” the whole infiltrated area resembling boiled sago or

tapioca. This seems to be a complete homogeneous coagulation or hyaline

necrosis of the whole mass out to the delicate fibrous mantle supplied

by the tissue in which the tubercle lies.

The organic distribution of tuberculous lesions has already received

some attention and is to be discussed with the orders. There are,

however, some localities affected conspicuously in the bird. The skin

lesions often attract attention during life. They occur around the eye,

at wing joints, on the cresta sterni and on the legs. Parrots and jays

have shown nodular or diffuse growths around the eye, originating both

in the lids and orbit, which on section have proved to be tuberculous.

These seldom ulcerate, but those upon the skin of the breast and wings

tend to have superficial erosions or deep ulcers. The latter lesions are

more common upon pigeons but have been seen in Psittaci and Galli.

Toucans and pigeons when pinioned, have on three occasions shown a

tuberculous mass on the stump.

[Illustration:

FIG. 52.—MASSIVE TUBERCULOSIS IN LIVER AND SEVERAL MURAL TUBERCLES OF

INTESTINE. COMMON PEA FOWL (PAVO CRISTATA).

]

[Illustration:

FIG. 53.—NODULAR HEPATIC LESIONS IN THE LIVER OF A DOVE.

]

Two parrots with hyperkeratosis of the beak and of the skin of the feet,

have also had tuberculosis. These have been mentioned in literature as

of tuberculous origin. One case well studied failed to show tubercle

bacilli in the corns. In the absence of tubercle bacilli, one is

inclined to think that this might be explained on the basis of a

circulating toxin such as is assumed to be responsible for hypertrophic

periosteitis. This latter condition has not been seen in birds.

Still another type of occasional occurrence deserves mention. While most

of the lesions in birds correspond to the description given in the

preceding pages, some lesions fail to degenerate in the centre,

retaining instead a solid homogeneous fleshy character of dull gray-

yellow color. Upon section these have been found wholly cellular in

construction. To distinguish them from the ordinary nodules they have

been designated tuberculomata. Lesions of this kind may occur along the

lymphatic paths, indeed seem more common in the lateral cervical and

thoracic chain, and upon bones and nerves. When they are numerous the

nodular caseous type is inconspicuous. They suggest the bovine infection

(Pearl disease), but one attempt to prove this failed. We are of the

opinion that this is the avian lymphatic form, as our examples

correspond to the literary descriptions of cervical tuberculous

lymphatics in birds. No especial variety of bird is more often affected

by this process.

Intestinal tuberculosis among the Aves may be said to assume three

forms. The best known, indeed the form usually spoken of as representing

the common picture, is that which produces varying sized nodules upon

the serosa, sometimes associated with adhesions to neighboring

intestines. Just how this type develops is not known. In some quarters

it is believed to originate by the penetration of the tuberculous

granulation tissue from the mucosa through the intestinal wall by

following lymphatic channels and that irregular contractions of the

musculature squeeze the exudate outward under the serosa. Other

observers think that the bacilli are carried _via_ the lymphatics to the

superitoneal tissue, there starting the tubercle. The truth of the

matter will probably be that both methods are operative although we have

seen more cases suggestive of the second than of the first explanation.

When these peritoneal nodules are numerous and prominent, mucosal ulcers

are uncommon and _vice versa_.

The second form is the ulcerative, flat ragged or crateriform defect

situated in a diffusely thickened wall. This was well illustrated in

cases of pulmonary infection in doves and guans, suggesting reinfection

of the gut tract from swallowed tubercle bacilli or a backward

development of the disease after the lungs were nearly solid.

The third form of tuberculous enteritis is quite interesting and

striking. It is best seen in the duodenal loop but may occur anywhere.

Diffuse thickening of the enteric wall is noted, and when palpation is

practiced a resilient but leathery sensation is obtained. Careful

inspection reveals the mucous surface to be velvety, a condition due to

a swelling, that is widening, of the villi which retain their erect

position and, when washed in flowing water, will be seen to move like a

field of grain in a breeze. The serosa may be, usually is, negative.

Studied microscopically the peculiarity of this form is in the

development of tubercles and diffuse cellular exudation in the villus

stalk, sometimes extending into the submucosa also. Round cell masses

like lymph follicles are sometimes prominent. This form is not

associated with any peculiar organic distribution so far as my studies

go.

[Illustration:

FIG. 54.—TUBERCULOUS MASSES OF INTESTINAL WALL SHOWING OUTWARD GROWTH.

SOMETIMES THESE MASSES OBSTRUCT THE LUMEN.

]

Passeres. The peculiarity of this order seems to be in the predominance

of the pulmonary route as origin of tuberculosis. Perhaps in no other

order has there been such extensive and advanced lesions as in these

little birds. Sometimes one whole lung will be solid while its fellow

will be half occupied by caseous material. The doves alone seem to

approximate the Passeres in ability to live with so much tuberculous

exudate.

Picariæ. Specimens from this order illustrate well the intestinal origin

and distribution of tuberculosis. There was, among these birds, one case

showing tuberculomata which was, because of its gross anatomy, listed as

the pearl type. Its description is as follows:

Lesson’s Motmot (_Momotus lessoni_). The region above and behind the

right clavicle in front of the brachial plexus on the internal surface

of the thorax, exterior to the first and second ribs, and on the

internal surface of the ribs at the junctions of ribs with the alæ of

the sternum, there are many small, irregular, smooth, firm, yellowish

white nodules varying in shape from spherical to sweet potato and in

size from 3 × 3 mm. to 3 × 7 mm. These are found quite homogeneous on

cross section. They do not resemble tubercle or mould infection but

make one think of neuromata. There are also a few present in the left

lateral air sacs, close to but not joining the intestine. The lungs

are apparently normal. Histological section of the masses described as

distributed along the nerves consist of sharply outlined but not well

encapsulated masses made up of irregularly disposed bunches of large

cells with vesicular nuclei in a stroma of loose connective tissue

very inconspicuous in amount. There is also quite a number of small

round cells and a few leucocytes. The large cells first described have

the nucleus eccentric for the most part. Many of them have two nuclei

and a few three and occasionally a giant cell is observed. Blood

vessels have a very delicate wall and are frequently encountered in

the centre of these masses. Atypical mitoses can be found. Here and

there a seal ring placement of the nucleus can be found. A few

eosinophiles are present not definitely placed. Necroses, with large

quantities of nuclear fragments, are scattered irregularly through the

mass. The diagnosis rests between an infectious granuloma, false

neuroma and sarcoma. Tubercle bacilli were found by stain in great

numbers both within and without the cells.

Psittaci. Tuberculosis occurs in this order somewhat more frequently in

the varieties whose habitat is the Eastern world, although South

American birds also suffer from it in the characteristic manner. There

seems to be no difference in the pathology of these two groups. Parrots

present very beautifully the separate solid or semisolid nodules of

avian tuberculosis, whether they be in the lungs, liver, or spleen. When

the lung becomes riddled with masses, coalescence occurs and the whole

mass turns into a cast of the hemithorax. Lesions in the liver are

mostly isolated, but the spleen often appears like one large pink

tuberculous nodule. The liver occupies as usual the first place in

organic incidence.

Striges. Owls (and Struthiones—see below) present the interesting

exception to the rule of intestinal origin of tuberculosis in birds.

Perhaps the platting is incorrect but the birds in the order under

discussion had older and much more advanced lesions in the lungs and

thoracic serosa than they did in the abdominal organs. That this was

true in all three examples is in itself noteworthy. Perhaps they possess

less pulmonary and more intestinal resistance. One of these birds showed

a small recent cavitation in the posteroinferior angle of one lung.

Accipitres. With one exception the cases of this order occurred among

the Falconidæ, that is in hawks, buzzards, and eagles. Their lesions are

usually generalized as indicated by the figures for visceral

distribution, but that half the number should have the oldest, most

prominent lesions in the lungs is curious. Their intestinal tuberculosis

seems mostly of the diffuse infiltrative type.

Columbæ. These birds are obviously the most susceptible of all the

varieties of which there are sufficient autopsies to make a comparison.

Generalized nodular lesions emanating from the intestinal tract comprise

their usual form, while most of the hepatic lesions are small miliary

and nodular; occasionally one sees caseous masses destroying large

sections of the organ. Their intestinal lesions may assume any of the

three forms described.

Galli. This is an order of something over the average percentage

incidence for the birds but containing families that seem very

susceptible to tuberculosis. The small number of Brush Turkeys

(_Catheturus lathami_) had 60 per cent. of the disease, while South

American Cracidæ had 44 per cent. These two groups raise the incidence

for the order. Galli as a group have generalized nodular tuberculosis

originating by the intestinal route. This is especially seen in the

Phasianidæ, while the very susceptible Cracidæ have much more prominent

lesions in the lungs, often of a massive caseous type. It is really

astonishing at times how much of the pulmonary tissue is occupied by

infiltrate before death has supervened.

Fulicariæ are represented by a special contingent of rails and

gallinules. Avian characters are well illustrated in the order. So too

the succeeding order, Alectorides, another variety of shore birds, run

true to the avian form. It is interesting to note that in the two cases

from each of these orders tuberculosis and aspergillosis have been

combined. The former has assumed the firm nodular type, while the

mycosis has been of the air sac variety. The following case is worth

citing as possibly illustrating infection _per cloacam_. There is,

however, no trace of this bird having been with a male with the disease.

Demoiselle Crane (_Anthropoides virgo_) ♀ . General tuberculosis

including the oviduct. All organs are thickly beset by caseous

tuberculous nodules except the lungs which have only a few scattered

ones. The oviduct is, for its lower two-thirds, much enlarged, firm,

tough, pale yellow, thickly beset with caseous nodules; upper parts

uninvolved. The kidneys are definitely enlarged, irregular, almost

mulberry-like, brownish yellow, firm and tough. On section the lobules

are irregular, connective tissue increased, urates in pelves.

Tubercles in intestines seem to be wholly peritoneal. This seems like

a tuberculosis of genital origin judging from condensation of

tubercles in the lower abdomen (mass around cloaca). The ovaries are

not involved. Lungs and thoracic air sacs relatively free. The

pericardium shows a whitish thickening of both layers due to the

presence of whitish granules like urates. Histological section of

kidney shows the capsule not greatly altered. Glomeruli largely

negative but a few show hyaline capsular thickening of vacuoles in

tufts or fibrosis in tufts or obliteration of whole structure. Tubules

largely degenerated, distended or distorted. Interstitial tissue

between the tubules definitely but irregularly increased. No real

attempt at regeneration. Few vessels show perivascular fibrous change.

One tubercle seen.

Anseres. These birds present no especial features so far as percentage

or organic incidence are concerned. The individuals are mostly geese and

swans, ducks being somewhat more often affected by mycosis than by

tuberculosis. However, both these diseases tend to assume the nodular

type in Anseres so that the diagnosis should be supported by

bacteriological discovery of the respective organisms.

Struthiones. The marked feature of this order is the prominence of the

isolated and confluent nodules in the lungs, of apparently greater age,

certainly of great size, than similar lesions in the abdominal viscera.

Caseation of the avian variety is well illustrated in these birds. The

thyroid body was involved in two of the three cases, the ovary in one.

The representatives of the Crypturi, two tinamous, came at the same time

and lived only a few months. Miliary tuberculosis of the small

precaseous variety was the form exhibited by both specimens.

HISTOLOGY OF THE TUBERCULOUS LESIONS.

The initial and characteristic unit of tuberculosis, the miliary

tubercle, seems to be constructed upon the same general principles in

all cases of the disease and in all members of the zoological groups in

our study and in a manner entirely comparable to that well known for man

and for the domestic animals. There are, however, certain minute

differences which are interesting and may at some time become important.

It is customary to speak of the bovine tubercle and of the human

variety, but there are also slight variations of the microanatomy of

each of these, while one may find on occasion a tubercle of the human

type in a cow and _vice versa_. Not all the domestic animals show the

bovine form, although in sheep and swine it is approximated very

closely. In the horse there is much greater tendency to a central

softening and fibrosis is not so common as in the bovine tubercle. I

have attempted to study the histological anatomy of each of the

zoological orders, but it has not resulted in any profitable discovery.

It is, however, possible to contrast the type commonly found in monkeys

with that characteristic for man and the ungulates and also to emphasize

the construction of the avian tubercle that it may be distinguished from

mammalian tuberculosis and from avian mycosis.

[Illustration:

FIG. 55. DIFFERENT VARIETIES OF THE MILIARY TUBERCLE.

A.—THE BOVINE FORM SHOWING THE NUMEROUS LANGHANS’ GIANT CELLS, THE

ABUNDANT SMALL EPITHELIOID CELLS. THE MODERATE NUMBER OF SMALL ROUND

CELLS, AND THE ACCOMPANYING CONNECTIVE TISSUE INCREASE. THERE IS

MODERATE CASEATION.

]

[Illustration:

FIG. 55. DIFFERENT VARIETIES OF THE MILIARY TUBERCLE.

B.—THE HUMAN TUBERCLE WITH CENTRAL COMPLETE NECROSIS. TYPICAL GIANT

CELLS, ABUNDANT EPITHELIOID CELLS AND THE RELATIVELY NARROW SMALL

ROUND CELL MANTLE.

]

[Illustration:

FIG. 55. DIFFERENT VARIETIES OF THE MILIARY TUBERCLE.

C.—THE TUBERCLE FREQUENTLY FOUND IN MONKEY TUBERCULOSIS. WITH RAPIDLY

ADVANCING CENTRAL NECROSIS ENCLOSING MUCH CHROMATIN DEBRIS. THE

ABSENCE OF LANGHANS’ GIANT CELLS. THE PRESENCE OF LARGE, PALELY

STAINING EPITHELIOID CELLS OF LANGHANS’ TYPE AND THE VERY SLIGHT

CIRCUMFERENTIAL REACTION.

]

[Illustration:

FIG. 55. DIFFERENT VARIETIES OF THE MILIARY TUBERCLE.

D.—AN AVIAN TUBERCLE WITH CENTRAL SHARPLY MARGINATED NECROSIS

CONTAINING MUCH CHROMATIN DEBRIS. THE IRREGULARLY ARRANGED

POLYNUCLEAR CELLS TYPICAL OF AVIAN TUBERCLES. THE SMALL NUMBER OF

REGULARLY ARRANGED EPITHELIOID CELLS. THE PAUCITY OF SMALL ROUND

CELLS AND THE PRONOUNCED CONNECTIVE TISSUE MANTLE.

]

The tubercle of the Primates is a loosely constructed affair lacking the

fibrous mixture of the bovine and the close cellular packing of the

human form. Studied from the periphery to the centre, there will be

found very little fibrocellular reaction in the immediately surrounding

organ, while the mantle of round cells, rather prominent in the human

tubercle, is often quite inconspicuous. The principal cellular component

of the miliary granuloma is the large pale endo- or epithelioid cell,

which is abundant, loosely arranged and without apparent purpose. In the

centre is an irregular necrosis usually retaining some chromatic matter,

probably the remains of recently destroyed nuclei, but this caseous

midpoint does not assume the dense acid staining common for many milia.

Giant cells of the Langhan’s or foreign body type are often entirely

missing, and when present are scanty. There may be large cells,

resembling the aforementioned epithelioid cells, with two or even three

large palely staining nuclei, but these latter are arranged irregularly

and not like the spokes of a wheel near the cell wall.

This picture suggests a rapidly growing inflammatory mass and indeed

this is the type that tuberculosis follows in monkeys. In a few cases

gross evidence of fibrosis in the serous surfaces and in the lungs has

been observed, but they are too rare to permit one to think that

connective tissue activity is an important part of the reaction of this

beast to the disease.

The avian tubercle as it rests in the tissue seems like a sharply

outlined almost encapsulated body. This is in part due to the

homogeneity of its structure and in part to the fibrocellular

condensation around the caseous part of the growths. Examined from

without inward, there is a round cell mantle, between the elements of

which course fine but easily perceptible fibrils; elastic tissue has

been seen among them. The small cells continue more deeply than the

fibres, to be succeeded in prominence by epithelioid cells of rather

dense character, the nuclei especially seeming quite rich in chromatin

and round. The rotundity of the nuclei remains not only in the single

separate cells forming the middle zone of the cellular cortex, but can

be found in the nuclei of the compound or giant cells which comprise the

internal layer lying upon the necrotic centre. These giant cells are

characteristic for the avian tubercle in assuming a form like syncytia

with nuclei arranged in irregular radiating columns. This internal large

cell area may completely surround the central necrosis or it may be

interrupted by the large single cells. Tubercle bacilli are more common

in and between single cells than multinuclear ones. Within the cellular

zone lies the necrotic centre, often, indeed usually, full of chromatic

debris. This centre is commonly quite amorphous but occasionally one

will see what is probably the remains of a coarse coagulum. Between the

necrosis and the cells one usually finds a split, a sort of separation

of the gangrenous from the living part. Old tubercles with denser

fibrous capsule retain this microanatomy in part, but the cellular zone

gradually becomes thinner and thinner until all that remains is a narrow

cortex of round cells and imperfectly retained multinuclear cells.

Tuberculous granulation tissue without definite milia consists entirely

of the round cells with small vacuoles and a fine but definite fibrosis.

Tuberculomata consist of cells of varying sizes with small round nuclei.

Interstitial fibrosis is delicate and barely visible unless especially

sought. Giant cells may be encountered but are not so large as in milia.

Necrosis occurs but not in an orderly manner in relation to cells as in

an isolated tubercle. Tubercle bacilli are very numerous.

[Illustration:

FIG. 56.—PHOTOGRAPH OF YOUNGEST AVIAN TUBERCLE AFTER COMPLETE

FORMATION.

]

[Illustration:

FIG. 57.—TUBERCULOMA, A SOLID TUMOR-LIKE MASS, CONSISTING OF CLOSELY

PACKED LARGE CELLS FITTED WITH RELATIVELY SMALL ROUND LOOSE NUCLEI.

THESE CELLS ARE CROWDED WITH BACILLI.

]

TYPES OF BACILLARY INFECTION.

According to experimental and statistical research, all the tubercle

bacilli of the higher vertebrate classes can be infective for any member

of these classes. Thus, for example, human bacilli have been found in

many orders of mammalia and in birds. The bovine form has been found in

swine. The lesson from this is that while the special predilection of a

variety of the tubercle bacillus may be for one kind of animal, it is

potentially a virus for other kinds. Hygienic principles have therefore

been laid down at the Garden which aim at the protection of all

specimens from every variety of tubercle bacillus. For this reason and

because the laboratory has not attempted extensive research on

bacteriology, few type determinations have been made and those at hand

offer nothing new or unusual; they are noted here as a matter of record.

Bovine bacilli have been judged by their slow growth and infectivity for

rabbits, human bacilli by the reverse of these characters. Avian

tubercle bacilli can be cultivated with reasonable ease directly from

lesions not bearing a mixed bacterial flora, and grow in a yellow,

moist, even, spreading colonization. In our two attempts at infection of

guinea-pigs, no success was had, although Rabinowitsch and others had no

difficulty in so doing; this strain may vary in virulence as do other

tubercle bacilli. No avian culture was obtained from a mammal, but a

bovine was found in a parrot and a human in a duck. Bovine bacilli were

isolated once from a monkey (see page 496) and in another case of

lymphatic type, bacilli of the short heavy blunt shape, supposed to be

characteristic of this variety of the germ, could be stained. Monkey

tuberculosis in our experience is usually due to the human tubercle

bacillus, judging by the staining characters and two successful

cultures.

DISCOVERY OF TUBERCULOSIS DURING LIFE.

Fully developed chronic tuberculosis may be recognized with reasonable

ease in the human being and some domestic animals. The diagnosis rests

largely upon the history and symptoms and partly upon the appearance of

the individual and upon signs elicited by physical examination. There is

good reason to believe that these latter methods are entirely applicable

to certain wild animals, notably those that can be caught and held

quiet, but because of their naturally great reserve many specimens offer

little reason for suspicion as to their tuberculous condition until near

death. Certain ungulates with chronic pulmonary disease get thin and

weak but remain on their feet with good appetite and satisfactory

discharges for many months. Primates, Carnivora, Rodentia and Aves not

uncommonly come to autopsy with very good coats and without great

emaciation and yet are heavily infected. It can be stated with fair

positiveness that no chain of historical data or gross observations are

certainly known to us as indicative of tuberculosis in the wild beast.

Coughing is not necessarily characteristic of chronic pulmonary

infection, although when continuous it rouses considerable suspicion,

especially in the Ungulata. It is to be interpreted with care in all

animals that have loose bedding as bits of straw or seeds get into the

throat causing irritation; the dust of hay may cause coughing in horses.

However much chronic or fatal tuberculosis may be interesting from the

standpoint of pathology or of zoological or visceral incidence, the most

important factors in our knowledge of the disease are its early

recognition and treatment, either for curative or hygienic purposes.

Since we have learned that advanced lesions may exist in an animal

without materially affecting its external appearance and behavior, it

naturally follows that early cases, possibly of an “open” or infectious

character are still less likely to give evidence of their existence.

This is well recognized by veterinarians as being true of cattle, but is

perhaps less well known, or possibly admitted, by those who handle the

very susceptible monkey.

Upon a visit to a foreign garden I was told that experience alone is

sufficient to enable an observer to detect tuberculosis, and that the

disturbance entailed in physical examination and tuberculin tests is

prejudicial to the well-being of all varieties, but especially the

delicate ones. I learned later that they had the disease in their

exhibition cages all the time but decided to put their method to the

test. Shortly after my return from abroad a splendid specimen of Grivet

Monkey (_Cercopithecus sabæus_) was condemned by the tuberculin test. He

was well studied by the superintendent and two very experienced keepers,

all of whom pronounced him one of the finest specimens they had ever

seen, and stated that he was behaving quite normally. Despite their

protests he was sacrificed, tuberculosis with early cavitation being

found in the upper lobe of the left lung. Incidentally vague physical

signs were found by auscultation, but as the monkey was unruly and had

long pectoral hairs little weight was placed on the observation.

However, it is frequently possible to make very thorough physical

examination of the lungs of the more tractable specimens, diagnoses of

pneumonia and bronchitis being frequently made in this and other parks,

so that treatment may be instituted.

IMPORTANCE OF TRANSMISSION AND KNOWN SUSCEPTIBILITY.

Some light upon possible reasons for the poor condition of an individual

animal is of course shed by a knowledge of the disease to which that

particular variety is most susceptible, to which may be added the data

obtained from previous deaths in the same group or enclosure. Thus, for

example, a sickly monkey would be suspected of having tuberculosis or

early osteomalacia, whereas no suspicion of these diseases would fall

upon the marsupials. The same position would be assumed if a dove and a

heron were out of condition.

In so far as enclosures are concerned, the matter is somewhat different.

Whenever a case of tuberculosis occurs in a cage, the remaining

specimens if any are removed and the place cleaned by soap and water and

disinfectant and paint. The naked flame from a blast lamp is used when

possible. Out-of-doors enclosures are vacated, spread with lime and

allowed to lie fallow for as long a time as practicable. These methods

have been in the main successful in clearing a cage of the disease, and

all our experience demonstrates the effect of cage hygiene and the

selection of non-infective replacements. A few places such as those

occupied by doves and guans have not been freed of infection, if one

judge by its appearance when new specimens are placed in them, but they

may of course be due to the infection from elsewhere. The history of

seven years in the new bird house where the hygienic conditions are

excellent, seems to indicate that a cage thoroughly cleaned is no longer

a source of danger, and that a repetition of tuberculosis in such an

enclosure is due to its importation with new exhibits.

The spread of the disease to nearby cages seems to depend upon two

factors. If the number of cases has been large and the infection

virulent, immediately adjoining cages are involved, but the tendency to

spread is directly proportional to the proximity of orders or families

that have a high susceptibility for tuberculosis. This second factor

seems to be the more important and is illustrated by our experience in

one corner of the new bird house. In this area are exhibited certain

doves and pheasants, among which are many cases, while the passerine

varieties nearby are little affected. So too in the flying cage the

disease has occurred in varieties with high general susceptibility.

There are at the present writing ten orders on exhibition in this large

enclosure and there have been more. An occasional case of the disease

occurs, but only in the orders which show it elsewhere. The Herodiones,

of which we have had nearly one hundred autopsies and many now are on

exhibition, are always well represented in this cage and yet show no

tuberculosis. In the ten orders mentioned above three show no cases of

the disease.

These observations illustrate the spread of tuberculosis, especially to

the most susceptible varieties, and how non-susceptibles under good

hygienic conditions fail to become infected even when infected animals

are near them. The freedom of activity in the large enclosure is

doubtless an important factor.

The history of the past three years with regard to the control of

tuberculosis in the small cages shows that twenty-nine were infected,

but by the measures employed nineteen have remained free of the disease

for one year; three of the remaining ten are known to have received

newly arrived and possibly infected specimens.

The accredited method of transmission in birds, the swallowing of

material soiled with the feces richly laden with germs, is the principal

reason why infected enclosures and their immediate environment are the

principal breeding places for tuberculosis. To be sure air currents may

blow the virus around, allowing it to light upon food in other cages but

this cannot be a great menace if for no other reason than that we have

had no epizoötic outbreak of the disease, when there were groups of

deaths in doves and guans.

Evidences with which to trace transmissions are much clearer in the

birds than in the mammals with the exception of monkeys and some

ungulates. Of course cases are perhaps too few in the carnivores and

rodents to permit correct deductions but it is very rare that more than

one case occurs in the same enclosure containing groups of these

varieties. Nor do animals in adjoining cages seem to “catch” the

infection. This observation does not suggest that any relaxation of

hygiene need be allowed but probably it implies that not many bacilli

are excreted by these animals; they cough very rarely. Groups of

ungulates (bison and deer) are often known to be infected but just how

it has arisen is seldom clear. Transmission from monkey to monkey has

been observed so frequently that it cannot be doubted, nor will anyone

wonder at it if reflection is given to the close personal contact of

these animals during their natural behavior. They huddle, pluck lice

from one another, take food from the mouth of another, bite and perform

many other actions greatly facilitating the transfer of any virus.

Bacilli may also be disseminated by coughing, drooling and with the

fecal discharges, for which latter there seems ample opportunity since a

notable percentage of cases have intestinal lesions. Monkeys do not seem

to raise sputum and expectorate it but they do eject saliva from their

lips.

Contraction of the disease from infected cages is believed to have

occurred at least once in our experience but the lesson of complete

sanitary cleaning of the enclosure learned from that happening, seems to

have enabled us to forestall its repetition.

THE TUBERCULIN TEST.

Tuberculosis presents the greatest single problem among the specific

infectious diseases which the director of a menagerie must attempt to

solve. Even though one may possess a knowledge of its zoological

distribution, clinical characters and pathological effects, these are

insufficient criteria for its detection at a stage when the animal might

be saved by treatment or, what is most important, removed from its

companions that they might be protected. To this end there remains but a

single procedure for the discovery of the existence of tuberculosis—the

use of tuberculin in one of its forms by one of its methods of

application. The use of this test in veterinary medicine needs no

commentary, having made its place in clinical and hygienic practice for

a quarter century or more. Armed with the knowledge of the satisfactory

use of the toxins of tubercle bacillus in cows, Dr. Penrose, Dr. C. Y.

White, Dr. A. E. Brown and Dr. Leonard Pearson began in 1901 a series of

experiments with old tuberculin of Koch which have led to the

development of a technique for its use in the detection of infected

monkeys. These interesting and instructive animals, being known as

highly susceptible since most of the collection died of the disease in

those days, and being handled with reasonable ease by experienced men,

were investigated as the most important specimens upon which to perfect

the method. Other varieties have been studied since and I shall refer to

them individually. The greatest amount of work and the most conspicuous

success attended the observations upon monkeys and the results of this

study are now in daily use in this Garden.

The work, conclusions and results, originated by Doctor Penrose, Doctor

White, and Doctor Brown can be described as one of the most completely

satisfactory series of observations in scientific medicine. Applying the

principle that a tuberculous animal reacts to the injection of

tuberculin by a temperature rise, the normal temperature curve of the

monkey was studied, that of the tuberculous monkey determined by killing

many specimens. This enabled them to state which animal was infected,

which was not and to place on exhibition only healthy specimens. Added

to this, strict hygienic principles in the housing and handling of the

animals have resulted in the elimination of the disease from our

exhibition house. Occasionally a case may develop, perhaps from feeding

by visitors, but the matter is no longer a problem. I know of no more

complete and satisfactory experiment and its practical application than

this work, which is condensed in the succeeding paragraphs.[101]

THE TEMPERATURE OF MONKEYS.

The success of the tuberculin test in the lower animals as in man

depends chiefly upon the alterations in temperature following the

injection of the toxin. It is generally admitted to-day that a healthy

animal’s temperature will not be affected by the introduction of this

material. There are in addition changes in the pulse and respiration

rate and in the physical signs but these are detected with difficulty

and are much less definite than thermometric records. The first

essential was therefore a thorough familiarity with the normal

temperature of the monkey, a requirement which met with considerable

difficulty from the beginning since the earliest observations revealed

puzzling irregularities. This necessitated the establishment of certain

regulations of technique which, after the preliminary tests, have been

found satisfactory enough to continue until the present day. All monkeys

are received in the quarantine rooms of the laboratory where they are

observed by the officials of the Garden and of the laboratory and there

they remain in separate cages until passed, as free from tuberculosis,

to the exhibition house.

The handling of monkeys for the purpose of taking temperatures is a

matter of no small importance since excitement will quite definitely

increase the registration. We have been fortunate enough to have in

charge of this work since its inception the same man, Keeper McCrosson,

who is thoroughly experienced in the care of these beasts and who can

catch and hold them with a minimum of disturbance. To him and to the

interested laboratory helpers much credit is due. Small specimens like

capucins and spider monkeys are caught with the gloved hand or with the

protection of a piece of heavy cloth. Larger specimens may be caught in

a net while strong monkeys are fitted with a collar and chain by which

they are pulled into the corner of the cage and held, while the door is

opened to permit a helper to catch the feet and arms. Two experienced

men can take the temperature of any monkey that can be handled at all

safely. The knowledge of how to do such work reduces the excitement of

the animal and renders more accurate the observation of its temperature.

During the period of temperature-taking food is given in small

quantities and only after the record is made.

Temperatures are taken in all animals by rectum,[102] the thermometer, a

separate instrument but always the same for each animal, well greased

with plain vaseline, being passed along the anterior rectal wall and

allowed to register for twice its indicated speed. During the

preliminary work, special instruments of officially standardized

accuracy were obtained by Doctor Brown but once the normals were

obtained, ordinary good thermometers registering from 94°F. to 108°F.

have been employed. If the record vary very much from the expected, such

as the figures obtained at the same time on the preceding day, or if the

rectum be crowded with feces, the instrument is shaken down and

reintroduced. In order to facilitate timing of exposures we use sand

glasses of three minute run.

After some experimentation by taking records at various times of day it

was found that monkeys as a group do not have a uniform temperature

during twenty-four hours but register a higher figure during daylight

than during darkness. This is probably due, as I shall discuss, to the

period of activity, not to the time of day. Figures obtained at various

hours indicated that the highest and lowest temperature would be

obtained if records were made at four-hour intervals at three, seven and

eleven o’clock AM. and PM. To give the normal temperature of a monkey,

the kind and the time of day are necessary adjuncts. Reference to forty-

eight hour charts which are used for the illustration of normal records,

and for contrast with tuberculin reactions later, will convey to the

reader a better idea of the normal daily rhythm of the simian heat

regulating system than would verbal description.

[Illustration:

CHART A. ORANG UTAN (Simia satyrus). Non-tuberculous at death.

]

NOTE.—In the temperature charts degrees indicated by circles and

connected by dashes are from records made after diagnostic tests by

injecting tuberculin.

The anthropoid apes (Curves A and B) have on the whole a mean

temperature nearer the human being than do the lower monkeys, but they

too present daily variables far greater than man. The high point of

their curve, at three PM., is in the neighborhood of 100°F. the lower

point around 97.5°F. From these charts and other records it can be said

that while the higher apes have a daily temperature curve with its high

point at three PM. and its low point at three AM., there is in them not

by any means the regularity of curve to be found in Cercopithecidæ and

Cebidæ. Our records of temperatures in the Hylobates (_Gibbons_) are not

extensive enough to quote but what we have approach those of the lower

monkeys.

[Illustration:

CHART B. CHIMPANZEE (Pan niger). Non-tuberculous at death.

]

Graphic curves of the normal temperatures of the various genera of

Cercopithecidæ and Cebidæ present striking similarities in the

regularity with which the daily rhythm is performed. In the seven genera

of which we have accurate records the normal high points fall between

102°–103°F. and the low points between 99°–100°F. while the curve of the

four-hourly steps is closely comparable. The curves D to J are

composites from charts of animals that have been tested with tuberculin,

which thereafter died or were killed and found free from tuberculosis.

Not every individual chart that may come to hand necessarily follows the

exact course detailed in these illustrative curves but these latter

offer a guide as to what is to be expected of the different varieties.

They show unequivocally the V-shaped curve of the temperature of the

monkey during twenty-four hours.

[Illustration:

CHART C. Composite chart of twenty-two non-tuberculous Lemures.

]

The Callitrichidæ or Hapalidæ have failed to show tuberculosis in our

Garden and little has been done upon them. As a matter of record there

is reproduced the only satisfactory chart at hand (K) taken very early

in the researches. It shows a similarity to those of the higher monkeys;

because of its very high afternoon record the animal was killed; no

tuberculosis was found.

[Illustration:

CHART D. Composite chart of eighteen non-tuberculous Cercopithecus.

]

The Lemures, being close to the Primates zoologically and presenting a

high incidence of tuberculosis, were included in this study.

Observations upon their normal temperature were hampered more than upon

that of monkeys and even to-day we cannot feel the same confidence in

the records. Irregularity is most marked and they seem easily disturbed

by handling. Chart C shows a composite temperature for forty-eight hours

of twenty-two proven non-tuberculous Lemures. The tendency for the

“night drop” is certainly existent but with much less definiteness than

in the Primates.

CONDITIONS WHICH MODIFY THE TEMPERATURE.

[Illustration:

CHART E. Composite chart of seventeen non-tuberculous Macacus.

]

Observations by A. E. Brown[103] and by Simpson and Galbraith[104] would

seem to indicate that the diurnal variation in monkeys is due to

periodicity of activity. Doctor Brown found that the temperature of a

night monkey is reversed, that it is higher during the dark than the

daylight hours. See chart of Potto (_Perodictus potto_) chart L. The

Scotch observers report that if the activity of day monkeys were

reversed, daytime being made artificially dark and activity forced

during the night, the temperature curves were likewise reversed.

[Illustration:

CHART F. Composite chart of eleven non-tuberculous Papio.

]

Perhaps the most important discoveries of these investigators concerned

the influence of excitement upon the temperature records. These

observers indicate definitely that the greater the physical activity and

nervous excitement the higher the thermometric record. We have noted

that the substitution of a strange keeper who may not be gentle and

tactful with the monkeys can serve to raise the temperature above the

records obtained by an experienced man with whose methods the animals

are familiar.

A knowledge of these facts dictates at least two important precautions

on our part—our specimens must be kept under identic conditions peculiar

to their kind, and surroundings must be established offering comfort

with a minimum of annoyance in transfer and handling. To this end all

specimens upon receipt are put into separate cages suitable to their

size and allowed to become accustomed to their surroundings for several

days before attempt at temperature-taking is made. Mention has already

been made of the experience and interest of the principal keeper; the

regularity of records is an attest to his work. Daily three o’clock

afternoon temperatures are taken first to accustom the animal to the

matter, before test records or tuberculin injections are made.

The existence of pathological states undoubtedly affects normal

temperature curves and tuberculin reactions. Gastroenteritis has the

effect of increasing the whole level and of making irregular the midday

and afternoon records. Respiratory tract disease cannot be said to have

a very definite effect; its most frequent influence seems to be to drive

the night records lower so that there is a long fall between seven and

eleven PM. and a long rise between seven and eleven AM.

THE TEST.

The preliminary rest of the new arrivals having passed daily three

o’clock afternoon temperatures are taken until an even level is

obtained; this requires usually four days but in very nervous specimens

it may be much longer. The afternoon temperature course provides not

only a means of teaching the monkey what is coming but supplies us with

a high point record for comparison. When a new variety is received, a

full normal twenty-four hour record is usually made. This preparatory

routine being fulfilled, the animal is injected under the skin of the

thigh or flank with freshly diluted mixed bovine and human tuberculin.

THE DOSAGE.

Early trials with this substance revealed the fact that a dosage based

upon the weight in comparison to man failed to elicit a definite

response whereas if based upon relative weight of cow was too large. The

finally determined quantity was arrived at, as was the case in early

human and bovine work, by experiment and trial and was as follows: A

monkey of five to ten pounds (2.3 to 4.5 kilos) received an initial dose

of 1. milligram and for each additional five pounds (2.3 kilos) 0.5 mg.;

this is 0.2 to 0.4 mg. per kilo. The amount given to man varies from 2.

to 5. mg.; if the body weigh 60 kilos this is 0.03 to 0.08 mg. per kilo.

Cows are given usually in this country 400 mg. or, for a cow of 250

kilos, 1.6 mg. per kilo. In the early work, doses comparable to the

figure for man failed, whereas at least two animals died very quickly

after 1.+ mg. per kilo; 5. mg. was the original high dose. While the

death of a monkey after a large dose was of no moment and was perhaps

desirable, it would only be the heavily diseased specimens and this

would give no criterion upon which to judge the appropriate dose for

all. Experience seems to warrant us in continuing with our present

figures since all tuberculous monkeys have reacted to it. Subsequent

cases for retest are increased from 50 to 100 per cent. depending upon

the size of the monkey, the very robust and vigorous ones receiving an

increase represented by the higher figure. One monkey injected eight

times has risen from 1. to 24. mg. with constantly a negative response

over a period of nine years.

Doses for Lemures are relatively higher, averaging 1.5 mg. or about 0.5

mg. per kilo; they are increased in the same manner as above.

THE TEMPERATURE TAKING.

Injections are usually made in the late forenoon, temperature records

being started at the usual three PM. hour and continued at four-hour

intervals for forty-eight hours, giving thirteen records over two days,

a time period presenting two complete cycles of diurnal variation. This

was found necessary because certain cases do not react during the first

day. Explanation of this was sought in the nature of the lesion but

could not be found further than that mild early lesions may give it but

it cannot be read as indicative of low activity since one case of

laryngeal tuberculosis had this “delayed reaction.” At times it has

seemed to occur when the injection fluid formed a blister under the

skin, a pocket in the areolar subcutaneous tissue, whence absorption

would be slow. Whatever the correct explanation, experience has

justified the recording of temperatures for full forty-eight hours.

[Illustration:

CHART G. Composite chart of five non-tuberculous Cynopithecus.

]

[Illustration:

CHART H. Composite chart of eleven non-tuberculous Ateles.

]

THE REACTION.

The experience gained with these monkeys supported definitely the

general opinion that tuberculin injected into healthy animals will not

disturb the temperature but will produce decided changes in that of

tuberculous animals. The reaction in the tuberculous animals may assume

several characters, of which usually two are combined in a chart. The

commonest and most convincing is a definite rise in the first twelve

hours, amounting to one degree or more; rarely it may be three degrees

(W). This is followed either by a maintenance of a high level or an

attempt to perform the night drop. It may be said that in general there

is an abortive attempt in nearly all tuberculin reactions to simulate

the V of the normal cycle; this can be seen in charts M, N, O and P.

Another rise may be attempted during a similar period of the second

twenty-four hours or the whole course may at that time approximate the

normal. A modification of this type of reaction is the performance of

the whole daily rhythm on a high level, set, as it were, by the initial

three PM. record. This form is confusing at times and has been

responsible for at least one of our mistakes. Combined with this high

level of curve is a tendency for the second twenty-four hours to be

higher than the first day (See Variegated Cebus Q and Sooty Mangabey R

and Chacma Baboon W). The second type of reaction, illustrated by chart

S, fails to resemble the normal daily cycle of the monkey temperature

but has sudden rises and falls as its characteristic feature. We have

learned to look with suspicion on all charts with sudden marked changes

of record even if they follow in the main a rhythmic course. The sudden

fall exhibited by a very sick monkey illustrated by Grivet Monkey (T)

and Campbell’s Monkey (U) is a bad sign. It has been met more often in

advanced caseous pulmonary tuberculosis than in any other tuberculous

lesion. On two occasions it has been seen in the absence of tuberculosis

so that retest is indicated if the specimen be valuable; such animals

however rarely survive the disturbance incident to the test as they are

usually suffering with some serious disease. Illustrative charts of

several positive reactions serve to elucidate their character better

than description. If comparison and contrast of the normal and post-

injectional temperature be made, the conclusions are definite.

[Illustration:

CHART I. Composite chart of eight non-tuberculous Cercocebus.

]

[Illustration:

CHART J. Composite chart of twenty non-tuberculous Cebus.

]

It cannot be said that any type of reaction indicates a particular form

of disease although the last type, the falling of the temperature beyond

the thermometric registration point, usually means advanced lesions

especially of the caseous pneumonic form. A very small lesion may give a

definite reaction as in Cebus (V).

[Illustration:

CHART K. GEOFFROY’S MARMOSET (Leontocebus geoffroyi). Non-tuberculous.

]

The examples given are those of a definite character but there are many

charts that vary from the normal upon which a decision is extremely

difficult to make. Such animals are held in quarantine to be retested

after the lapse of three months. Early in the work a suspected specimen

was reinjected after two weeks, failed to give a reaction but died in

about two months of tuberculosis. The nullification of the test by

previous injections of tuberculin is well known. Three months’ interval

permits a disappearance of the non-sensitivity and allows any latent

tuberculosis, possibly stimulated by the toxin, to develop. Repetition

upon the same monkey has occurred as high as ten times without apparent

harm.

[Illustration:

CHART L. POTTO (Perodicticus potto). Healthy.

]

There are sometimes in human beings local reactions at the point of

injections. These have been entirely lacking from our monkey specimens.

Nor have we ever seen secondary tuberculous lesions appear at the point

of the needle-stick. Aseptic syringes and generally cleanly technique

have also protected against local abscesses. When an animal is injected

he may scratch or pick at the spot for a minute or two but thereafter

seems to ignore it entirely.

[Illustration:

CHART M. MONGOOSE LEMUR (Lemur mongoz). Tuberculous.

]

[Illustration:

CHART N. BLACK HANDED SPIDER MONKEY (Ateles geoffroyi). Tuberculous.

]

RESULTS.

The value of the test can best be estimated by a recital of the

mortality of monkeys, from tuberculosis, since its inception. Before the

test was started practically every monkey in the collection for

sufficient length of time to be exposed died from the disease. The

average duration of exhibition life of all specimens up to 1903 did not

exceed eleven months. The time has risen almost uninterruptedly until

now it is thirty-five months. There are, at time of writing, sixty-eight

specimens in the cages which have been on view from one to one hundred

and eighty-five months with an average of fifty-four months. These

figures speak for themselves as evidence of the reduction of infection.

The average mortality from enteritis and degenerative bone disease has

remained about the same through all these years. Percentage figures such

as are recorded in our yearly report are misleading because all monkeys

written into the property record of the Garden are listed and since some

of these specimens remain in quarantine, they do not properly belong to

the exhibition collection. Up to 1906 when the test technique was

perfected nearly all deaths were due to tuberculosis, the figure for

1906 (including experimental animals) being 78 per cent. However from

February 1906 to October 1907 and from then until May 1910 no case of

tuberculosis occurred in the exhibition cages and both deaths at these

given times seem like infection from visitors. During the next three

years thirteen monkeys died of the disease in the exhibition and many

more in quarantine. By 1913 the outbreak was stamped out. Its

explanation is not so very far to seek. In the fall of 1910 we obtained

some suspected monkeys which were kept in one of the quarantine rooms.

After repeated testing two were passed. From them five cases are known

to have originated and it was not until in 1912 when the whole

exhibition house was cleaned of specimens, thoroughly disinfected and

fumigated and until every specimen was retested, that the infection

passed. In 1914 no cases occurred, while in 1915 a case either slipped

through undetected or was a visitor infection; 1916 two cases, 1917 one

case, 1918 one case (see orangutan charts), 1919 and 1920 none and 1921

one case, 1922 no cases. Since 1912 the whole monkey collection has been

tested every two years, a method which enabled us to catch a small group

in 1916 and has protected the collection since then. Three of the six

monkeys specified above were never placed free in the general cages of

the exhibition house, they being segregated in smaller cages. One, the

orang, was with its mate in an isolated cage. The other two were in

larger cages and their history suggests visitor infections.

[Illustration:

CHART O. RHESUS MACAQUE (Macacus rhesus). Tuberculous.

]

[Illustration:

CHART P. ORANG UTAN (Simia satyrus). Tuberculous.

]

We have never underestimated the possibility that an occasional very

early case might evade detection by this test but we believe the history

just outlined warrants us in depending upon it for the protection of the

exhibition. By the tuberculin test we have detected the existence of the

disease in twenty-three per cent. of specimens. Every condemned

specimen, forty-one, showing tuberculosis, gave a positive test. Fifteen

monkeys condemned on their temperature charts failed to show the

disease. Eight per cent. of the tests resulted in suspicious charts, and

the animals finally died of the disease in quarantine. Fifty-six

tuberculous monkeys died on exhibition, of which thirty-one were

original there and twenty-five their contacts. Twelve of the thirty-one

were in the early stages of the work, thirteen due to our misadventure

of 1910 and the remainder, six, scattered over nine years.

[Illustration:

CHART Q. VARIEGATED CEBUS (Cebus variegatus). Tuberculous.

]

[Illustration:

CHART R. SOOTY MANGABEY (Cercocebus fuliginosus). Tuberculous.

]

Another interesting experience concerns the exhibition of a group of

Rhesus Macaques in an open “band stand” cage. The idea arose in an

attempt to find a separate exhibition space for some good specimens that

gave unsatisfactory charts, with the purpose of applying at the same

time the “open air” treatment if tuberculosis existed. The experiment

has been entirely successful since in the eleven years during which this

enclosure has been used there has been but a single case of tuberculosis

among twenty-six monkeys. Curiously enough this exception gave a good

chart and we suspect it was a visitor infection; no secondary case arose

from it. The animals housed in this cage keep in excellent condition,

their coats responding to our severe winter by increasing in thickness

and glossiness. Frozen toes, fingers and tails are sometimes seen but

these monkeys seem just as happy as the others. Breeding is active and

the young are lusty and husky. Practically the only deaths are due to

accident, or to abuse of old and less vigorous members of the colony. We

are unable to give comparative exhibition periods and death rates for

monkeys in the large house and this open cage because some specimens

have been changed from one to the other but it is certain that the

appearance of the “band stand” monkeys is better than those in the house

and there are four of eleven animals in the former which have been there

eleven years and only four among the seventy in the exhibition house for

that length of time.

[Illustration:

CHART S. VERVET MONKEY (Cercopithecus lalandii). Tuberculous.

]

[Illustration:

CHART T. GRIVET MONKEY (Cercopithecus sabæus). Tuberculous.

]

The results of the foregoing work seem to demonstrate that the

tuberculin test permits the separation of tuberculous and non-

tuberculous monkeys and that its employment serves the purpose of

maintaining a healthy exhibition by excluding infected specimens. These

experiences form further corroboration of the facts that tuberculosis

begets tuberculosis, that a healthy individual is not a source of

infection. It follows that an obviously tuberculous animal should not,

need not, be a source of danger; the hidden or unrecognized case is the

menace. There is little or no problem when an unequivocally good or bad

temperature record is obtained; it is when there are slight variations

from the standard for the group that decision as to the disposition of

the specimen must be made. Nearly always such specimens are retested

until the records are definite. If they be constantly irregular the

animal is either sacrificed or exhibited in a separate cage far from

other monkeys. It is by the sacrificing of infected specimens or the

segregation of suspected ones that our collection is kept clear of

disease.

[Illustration:

CHART U. CAMPBELL’S MONKEY (Cercopithecus campbelli). Non-tuberculous.

(See page 533).

]

Hygiene of a general character must be maintained also. Our quarantine

rooms are disinfected by formaldehyde and mechanical cleansing after

every case detected as tuberculosis, and painted every two years.

Monkeys associated with infected ones, are retested and then given a

bath of carbolized water before being put on exhibition. The exhibition

house is mechanically and chemically disinfected at the injection time

each two years. All keepers are examined for tuberculosis upon beginning

their employment and those handling monkeys, periodically thereafter.

When a case of tuberculosis dies, all animals in the same and adjoining

cages are removed for retest and the enclosure scrubbed and disinfected.

[Illustration:

CHART V. WEEPER CEBUS (Cebus capucinus). Tuberculous.

]

There is a source of tuberculosis upon the importance of which we can

only speculate—the visitor. There were two isolated cases in animals

which had passed the test with unexceptionable charts, three and four

months on exhibition; curiously enough no other cases occurred in their

cages. These we have laid to visitor infection since no previous

exposure can be traced for the specimens and no secondary cases

occurred.

I can conclude this discussion of the tuberculin test and of the control

of tuberculosis by its use, by mentioning the possibilities for the

solution of the problem in man. While the eradication of the disease

cannot be accomplished as easily as if a potential source could be

eliminated by sacrifice, it will come in direct relation to the

earliness of detection of infection and isolation of the sources of

danger. Not so much the cough-racked consumptive but the unrecognized

early lesion whose bearer hawks and spits in public places or at home,

unaware of his malign power!

[Illustration:

CHART W. CHACMA BABOON (Papio porcarius). Tuberculous.

]

THE SKIN AND EYE TESTS WITH TUBERCULIN.

The first of these can be dismissed briefly, for in a few cases it was

absolutely of no value. A known tuberculous monkey was injected _into_

the skin of the chest with 0.5 mg. of old tuberculin. The small bleb

disappeared in a few hours and was followed by no reaction whatsoever.

Other attempts likewise failed, some of them I believe due to the

technical difficulty of injecting into the skin. This tissue is very

thin, delicate and loose at the less hairy places where a reaction might

be read—arm, chest, abdomen. The hairless parts of the rump might be

used, but are so often scratched and soiled with dirt that readings

might be misleading. The Von Pirquet test was done on the first

mentioned specimen and was likewise negative. His tuberculin test was

afterward positive.

[Illustration:

CHART X. BLACK APE (Cynopithecus niger). Tuberculous.

]

The ophthalmic reaction is highly spoken of in the New York Zoological

Park and has been used elsewhere. It was tried by me at the time Doctor

Blair first discussed it, but with variable results. One set of two

monkeys was treated with Calmette’s purified tuberculin into the

conjunctival sac and given a subcutaneous dose of old tuberculin.

Another set received 1 per cent. old tuberculin into the conjunctivæ and

the usual subcutaneous dose. Although all these monkeys gave a

temperature reaction only one gave a conjunctival reaction. Fearing that

the two tests simultaneously might be an unfair trial, another poor

specimen was given an eye test which resulted negatively; a later

subcutaneous test and autopsy revealed the disease. Because of these

experiences and the fear that any reacting conjunctivæ might become

secondarily infected from the uncertain personal hygiene of the beast,

we decided to omit this method and rely upon the temperature test.

PATHOLOGICAL EFFECTS OF THE INJECTION OF TUBERCULIN.

It is generally believed that tuberculin injected into tuberculous

animals, in doses large enough to produce a marked reaction at the site

of disease, may stimulate the process to growth and spread and that

certain parenchymatous organs in such bodies undergo degenerative

changes. We can give little information concerning the first point

because known infected animals have not been sacrificed during the test

and we are not informed of the degree of morbid lesion in those dying,

since we had no previous knowledge of its existence.

[Illustration:

FIG. 58.—EFFECT OF TUBERCULIN ON THE KIDNEY. AN UNUSUALLY SEVERE

REACTION IN THE RENAL TUBULES AND INTERSTITIAL TISSUE FOLLOWING A

TEST DOSE OF TUBERCULIN. SUCH A MARKED CHANGE SUGGESTS THAT IN THIS

CASE PRE-EXISTING RENAL DAMAGE WAS AGGRAVATED. THE ANIMAL WAS

TUBERCULOUS BUT HAD NO LESIONS IN THE KIDNEY.

]

An interesting and practically useful observation has, however, been

made upon the kidneys of several monkeys dying shortly after tuberculin

injection. It consists in a marked cloudy swelling of the renal

epithelium and a congestion or even thrombosis of the glomerular

capillaries, accompanied sometimes by increase of nuclei in the tuft and

by amorphous material in the space of Bowman. Grossly such kidneys are

but little changed, albeit the cortical zone may be dull and opaque and

swell out slightly on section; very occasionally bloody streaks may

separate the cortical and medullary striæ. In a few kidneys there have

been suggestions of preëxisting nephritis but usually the findings are

confined to those given above. At all events true glomerulonephritis is

not often found. Monkeys which have this condition may or may not

exhibit a behavior suggesting its existence. Sometimes it will be noted

that the animal is dull and eats little, at other times the keeper will

report that the cage is seldom wetted and we know of cases in which only

an ounce or two of urine has been passed in a day. Two monkeys were

distinctly ataxic and incoördinate and one of these had a convulsion.

From one a specimen of urine showed albumen but no casts.

These signs of renal affection are not always alone nor are the kidneys

necessarily the only part diseased since postmortem records show a

variety of accompanying lesions, bronchitis and enteritis, for example.

There are, however, several cases dying in a few days after tuberculin

injection, both with and without tuberculosis, in which the renal

changes were quite prominent; two examples, without tuberculosis,

exhibited the damage to the kidneys very well and with no other evident

visceral pathology. The relation of cause and effect may not be

unequivocal, but these findings suggest that the condition of the

kidneys deserves attention when tuberculin is to be injected. My

associate, Dr. Corson-White, is firmly convinced that the substance

whips up a preëxistent parenchymatous disease and wants to see a

urinalysis from every monkey that is in any way abnormal.

THE TUBERCULIN TEST IN OTHER ANIMALS.

Two cases of tuberculosis occurred in White nosed Coatis (_Nasua

narica_) so that it was decided to test their neighbors in the next

cage. There is reproduced a composite (Y) of the temperature record of

three of these animals after receiving 2 mg. of tuberculin under the

skin. No tuberculosis was found in them at death, all dying within two

years. The similarity to the primate type of temperature curve is

striking.

Chart Z shows the course of temperature before and after tuberculin

injection in a Bactrian Camel (_Camelus bactrianus_) ♀ which lived for

some months and showed no infection at autopsy.

Charts AA and BB show the temperature ranges of respectively a healthy

and a tuberculous Bison (_Bison bison_.)

Chart CC is that of a Malayan Sambur Deer (_Cervus equinus_) which died

a week after injection, showing fibrocaseous tuberculosis. The failure

to make an initial rise is noteworthy, but the fall in temperature may

be explained by the severity of the lesions and the approaching death.

Chart DD represents daily and post-injection records of a Virginia Deer

(_Cervus virginianus_) which at death was found free of the disease.

Chart EE is that of a healthy American Elk (_Cervus canadensis_).

[Illustration:

CHART Y. Composite chart of three non-tuberculous coatis.

]

[Illustration:

CHART Z. BACTRIAN CAMEL (Camelus bactrianus). Non-tuberculous.

]

[Illustration:

CHART AA. AMERICAN BISON (Bison bison). Non-tuberculous.

]

[Illustration: