time, Brigadier General Leonard Wood, was a man who had
received a thorough medical training; broad and clear-minded,
he fully appreciated the importance of what might be the
outcome of our researches. We found in him the moral support
which we so much needed and, further, he promptly placed at the
disposal of the board sufficient funds with which to carry on
the experiments to the end. I firmly believe that had other
been the circumstances, had a more military and less scientific
man been at the head of the government, the investigation would
have terminated there and then, and many years would have
passed, with hundreds of lives uselessly sacrificed, before we
could have attained our present remarkable sanitary triumphs.
We immediately set about choosing a location for our camp. I
had already looked over the ground, preferring the proximity of
Camp Columbia, from where supplies could be easily obtained and
because the Military Hospital there could be used for treating
the cases that we intended to produce; I was therefore
favorably impressed with the seclusion offered by a spot
situated a short distance from the main road, in a farm, named
San Jose, belonging to my friend Dr. Ignacio Rojas, of Havana.
Major Reed decided upon this place after looking at many others
in the neighborhood, so that on the twentieth of November we
inaugurated our camp, which we named Camp Lazear, in honor to
the memory of our dead colleague, consisting then of seven army
tents, guarded by a military garrison, composed of men who had
been carefully selected by virtue of their previous good record
and their interest in the work to be undertaken.
Feeling that we had proved, to ourselves at least, the agency
of the mosquito in yellow fever, it became our duty to disprove
the theory, until then held as a certainty by many authorities,
to the effect that the soiled bedding and clothing, the
secretions and excreta of patients, were infectious and in some
way carried the germ of the disease. We therefore designed a
small wooden building, to be erected a short distance from the
tense, with a capacity of 2,800 cubic feet. The walls and
ceiling were absolutely tight, the windows and vestibuled door
screened and all precautions taken to prevent the entrance of
insects.
Into this, called the "infected clothing building," three beds
and a stove, to maintain a high tropical temperature, were
introduced; also mattresses and pillows, underwear, pajamas,
towels, sheets, blankets, etc., soiled with blood and
discharges from yellow fever cases: these articles were put on
the beds, hung about the room and packed in a trunk and two
boxes placed there for the purpose.
The building was finished and equipped on November 30. That
Friday evening, Dr. Robert P. Cook, U. S. Army, with two other
American volunteers, entered it and prepared to pass the night:
they had instructions to unpack the boxes and trunk, to handle
and shake the clothing and in every way to attempt to
disseminate the yellow fever poison, in case it was contained
in the various pieces. We watched the proceedings from the
outside, through one of the windows. The foul conditions which
developed upon opening the trunk were of such a character that
the three men were seen to suddenly rush out of the building
into the fresh air; one of them was so upset that his stomach
rebelled; yet, after a few minutes, with a courage and
determination worthy only of such a cause, they went back into
the building and passed a more or less sleepless night, in the
midst of indescribable filth and overwhelming stench.
For twenty consecutive nights these men went through the same
performance; during the day they remained together, occupying a
tent near their sleeping quarters. Dr. Cook, by voluntarily
undergoing such a test, without remuneration whatsoever, proved
his faith in the mosquito theory; his demonstration of the
harmless character of so-called infected clothing, in yellow
fever, has been of the greatest importance. The other six men
(two of them with Dr. Cook) who were subjected to this test,
received each a donation of one hundred dollars for his
services.
Many days even before the establishment of the experimental
camp, the board had heard that several men who knew of our work
were willing to submit to the inoculations and thus aid in
clearing up the mystery of yellow fever. Two of these require
special mention, John R. Kissinger, a private in the Hospital
Corps of the Army, was the first to offer himself most
altruistically, for, as he expressed it, his offer was made
without any desire for pecuniary or other consideration and
solely "in the interest of humanity and the cause of science,"
the other, J. J. Moran, a civilian employee, also stipulated as
a condition that he was to receive no pay for his services.
Both these men, in due time, suffered from yellow fever and
until very recently had never obtained any reward for the great
risk which they ran so voluntarily and praiseworthily.
Kissinger, who after several years' service in the army became
disabled, is receiving a pension from the government; Moran, I
hope, is still well and in the employ of the Isthmian Canal
Commission, justly enjoying the friendship and confidence of
his superior officers. The names of Kissinger and Moran should
figure upon the roll of honor of the U. S. Army.
On the day the camp was definitely organized, Kissinger, who
had not gone outside the military reservation for more than a
month, moved into Camp Lazear and received his first bite from
a mosquito which evidently was not "loaded" for, again on
November 23, he was stung by the same insect without result. On
December 5, five mosquitoes were applied, which brought about a
moderate infection in three days. Moran was also bitten by
mosquitoes which were supposed to be infected on November 26
and 29, both times unsuccessfully. As will be seen, he was
infected later on.
By this time we had decided, the weather having cooled
considerably, that it was better to keep the mosquitoes at a
higher temperature and nearer to the men who were to be
inoculated; therefore it was planned to put up another small
wooden structure, which was to be known as the "Mosquito
Building" in which an artificial temperature could be
maintained; at my suggestion, the building was so designed that
it might serve to infect individuals; by liberating infected
mosquitoes on the inside and exposing some person to their
stings, we could try to reproduce the infection as we felt it
occurred in nature. Another reason for the mosquito house was
the need to obviate the transportation of the insects from the
Military Hospital, where I kept them, to our camp, which could
not be easily done without subjecting them to severe injury.
Upon one occasion I was taking four infected mosquitoes in the
pocket inside my blouse from the laboratory in Havana to the
experimental camp, accompanied by my attendant Private Loud;
the horse which pulled my buggy, a rather spirited animal,
becoming frightened at a steam roller, as we went around the
corner of Colon Cemetery, started to race down the hill towards
the Almendares River: Loud was thrown out by the first
cavortings of the horse, who stood on its hind legs and jumped
several times before dashing away, while I held tightly to the
tubes in my pocket, as the buggy upset and left me stranded
upon a sand pile in the middle of the road; the mosquitoes were
quite safe, however, and upon my arrival at Camp Lazear I
turned them over to Carroll for his subsequent care.
Another difficulty afterwards encountered was the scarcity of
material susceptible to infection, for, although several men
had expressed a willingness to be inoculated, when the time
came; they all preferred the "infected clothing" experiment to
the stings of our mosquitoes. We then thought best to secure
lately landed Spaniards, to whom the probable outcome of the
test might be explained and their consent obtained for a
monetary consideration. Our method was as follows; as soon as a
load of immigrants arrived, I would go to Tiscornia, the
Immigration Station across the Bay of Havana, and hire eight or
ten men, as day laborers, to work in our camp. Once brought in,
they were bountifully fed, housed under tents, slept under
mosquito-bars and their only work was to pick up loose stones
from the grounds, during eight hours of the day, with plenty of
rest between. In the meantime, as the days of observation
passed, I carefully questioned them as to their antecedents,
family history and the diseases which they might have suffered;
those who had lived in Cuba or any other tropical country
before were discarded at once and also those who were under age
or had a family dependent upon them. When the selection was
finally made, the matter of the experiment was put to them.
Naturally, they all felt more or less that they were running
the risk of getting yellow fever when they came to Cuba and so
were not at all averse to allow themselves to be bitten by
mosquitoes: they were paid one hundred dollars for this, and
another equal sum if, as a result of the biting experiment,
they developed yellow fever. Needless to say, no reference was
made to any possible funeral expenses. A written consent was
obtained from each one, so that our moral responsibility was to
a certain extent lessened. Of course, only the healthiest
specimens were experimented upon.
It so happened that some reporter discovered what we were
about, or perhaps some invidious person misrepresented the
facts; at any rate, on the twenty-first of November a Spanish
newspaper appeared with flaring headlines denouncing the
American doctors who were taking advantage of the poor
immigrants and experimenting with them by injecting all sorts
of poisons! It called upon the Spanish consul to look after his
subjects. In view of this we felt that if such campaign
continued, in a short time it would either make it impossible
to secure subjects or cause diplomatic pressure to be exerted
against the continuance of our experiments. It was thought best
to "beard the lion in his den" so the three of us called upon
the consul the following day. He was surprised to hear one of
us address him in his own language, having taken us all for
Americans on first sight, and when I explained to him our
method of procedure and showed him the signed contracts with
the men, being an intelligent man himself, he had no objections
to offer and told us to go ahead and not bother about any howl
the papers might make.
The first three cases (two of them Spaniards) which we produced
came down with yellow fever within a very short period, from
December 8 to 13; it will therefore not surprise the reader to
know that when the fourth case developed on December 15, and
was carried out of the camp to the hospital, it caused a
veritable panic among the remaining Spaniards, who, renouncing
the five hundred pesetas that each had in view, as Major Reed
very aptly put it, "lost all interest in the progress of
science and incontinentally severed their connection with Camp
Lazear."
But there was a rich source to draw from, and the unexpected
stampede only retarded our work for a short time. Our
artificial epidemic of yellow fever was temporarily suspended
while a new batch of susceptible material was brought in,
observed and selected. The next case for that reason was not
produced upon a Spaniard until December 30.
In the face of the negative experiments with supposedly
contaminated articles, it rested with us to show how a house
became infected and for this purpose the main part of the
"mosquito building" was utilized.
This chamber was divided into two compartments by a double
wire-screen partition, which effectually prevented mosquitoes
on one side from passing to the other; of course there were no
mosquitoes there to begin with, as the section of the building
used for breeding and keeping them was entirely separated from
the other, and there could be no communication between them.
On the morning of December 21, a jar containing fifteen hungry
mosquitoes, that had previously stung cases of yellow fever,
was introduced and uncovered in the larger compartment, where a
bed, with all linen perfectly sterilized, was ready for
occupancy. A few minutes after, Mr. Moran, dressed as though
about to retire for the night, entered the room and threw
himself upon the bed for half an hour; during this time two
other men and Major Reed remained in the other compartment,
separated from Moran only by the wire-screen partition. Seven
mosquitoes were soon at work upon the young man's arms and
face; he then came out, but returned in the afternoon, when
five other insects bit him in less than twenty minutes. The
next day, at the same hour of the afternoon, Moran entered the
"mosquito building" for the third time and remained on the bed
for fifteen minutes, allowing three mosquitoes to bite his
hands. The room was then securely locked, but the two Americans
continued to sleep in the other compartment for nearly three
weeks, without experiencing any ill effects.
Promptly on Christmas morning Moran, who had not been exposed
to infection except for his entrance into the "mosquito
building" as described, came down with a well-marked attack of
yellow fever.
The temperature in this room, where these mosquitoes had been
released, was kept rather high and a vessel with water was
provided, where they might lay their eggs if so inclined, but
notwithstanding all these precautions, it was subsequently
found that the insects had been attacked by ants, so that by
the end of the month only one of the fifteen mosquitoes
remained alive.
It is hardly necessary to detail here how seven other men were
subjected to the sting of our infected mosquitoes, of which
number five developed the disease, but it may be interesting to
note that two of these men had been previously exposed in the
"infected clothing building" without their becoming infected,
showing that they were susceptible to yellow fever after all.
The evidence so far seemed to show that the mosquito could only
be infected by sucking blood of a yellow-fever patient during
the first three days of the disease; to prove that the parasite
was present in the circulating blood at that time we therefore
injected some of this fluid taken from a different case each
time, under the skin of five men: four of these suffered an
attack of yellow fever as the result of the injection. The
other one, a Spaniard, could not be infected either by the
injection of blood or the application of mosquitoes which were
known to be infected, showing that he had a natural immunity
or, more likely, that he had had yellow fever at some previous
time.
While selecting the Spaniards, it was often ascertained that
they had been in Cuba before, as soldiers in the Spanish army
usually, and the natural conclusion was that they had undergone
infection; it was very seldom that any escaped during the
Spanish control of the island.
Thus terminated our experiments with mosquitoes which, though
necessarily performed on human beings, fortunately did not
cause a single death; on the other hand, they served to
revolutionize all standard methods of sanitation with regard to
yellow fever. They showed the uselessness of disinfection of
clothing and how easily an epidemic can be stamped out in a
community by simply protecting the sick from the sting of the
mosquitoes and by the extensive and wholesale destruction of
these insects which, added to the suppression of their breeding
places, if thoroughly carried out, are the only measures
necessary to forever rid a country of this scourge.
Besides keeping a sharp lookout against the importation of
yellow fever cases, these are the simple rules that have kept
the Panama Canal free and prevented the slaughter of hundreds
of foreigners, so generally expected every year, in former
times.
Since we made our demonstration in 1901, our work has been
corroborated by various commissions appointed for the purpose,
in Mexico, Brazil and Cuba, composed variously of Americans,
French, English, Cuban, Brazilian and German investigators.
Nothing has been added to our original findings; nothing has
been contradicted of what we have reported, and to-day, after
nearly thirteen years, the truths that we uncovered stand
incontrovertible; besides, they have been the means of driving
out yellow fever from Cuba, the United States (Laredo, Texas,
1903 and New Orleans, La., 1905), British Honduras and several
cities of Brazil.
Of the Army Board only I remain. Lazear, as reported, died
during the early part of our investigations; Reed left us in
1902 and Carroll only five years later. The reader may wonder
of what benefit was it to us, this painstaking and remarkable
accomplishment which has been such a blessing to humanity! See
what the late Surgeon General of the U. S. Army had to say in
his report (Senate Document No. 520, Sixty-first Congress,
second session):
1. Major Walter Reed, surgeon, United States Army, died in
Washington, D. C., from appendicitis, November 23, 1902, aged
51. His widow, Emilie Lawrence Reed, is receiving a pension of
$125 a month.
2 Maj. James Carroll was promoted from first lieutenant to
major by special act of Congress, March 9, 1907. He died in
Washington, D C., of myocarditis, September 16, 1907. His
widow, Jennie H. Carroll, since his death, has received an
annuity of $125 a month, appropriated from year to year in the
Army appropriation bill.
3. Dr. Jesse W. Lazear, contract surgeon, United States Army,
died at Camp Columbia, Cuba, of yellow fever, September 25,
1900. His widow, Mabel M. Lazear, since his death, has received
an annuity of $125 a month appropriated from year to year in
the Army appropriation bill.
4. Dr. Aristides Agramonte is the only living member of the
board. He is professor of bacteriology and experimental
pathology in the University of Habana and has never received,
either directly or indirectly, any material reward for his
share in the work of the board.
It is not for me to make any comments: the above paragraphs
have all the force of a plain, truthful statement of facts.
Perhaps it is thought that enough reward is to be found in the
contemplation of so much good derived from one's own efforts
and the feeling it may produce of innermost satisfaction and in
forming the belief that one had not lived in vain. In a very
great measure, I know, the thought is true.
THE EVOLUTION OF THE STARS AND THE FORMATION OF THE EARTH. IV
BY WILLIAM WALLACE CAMPBELL
DIRECTOR OF THE LICK OBSERVATORY, UNIVERSITY OF CALIFORNIA
THE PLANETESIMAL HYPOTHESIS
THE most elaborate structure yet proposed to explain the origin
of the solar system is the planetesimal hypothesis by
Chamberlin and Moulton. The energy which these investigators
have devoted to formulating and testing this hypothesis, in the
light of the principles of mechanics, has been commensurate
with the importance of the subject. They postulate that the
materials now composing the Sun, planets, and satellites, at
one time existed as a spiral nebula, or as a great spiral swarm
of discrete particles, each particle in elliptic motion about
the central nucleus. The authors go further back and endeavor
to account for the origin of the spiral nebula, but this phase
of the subject is not vital to their hypothesis. However, it
conduces to clearness in presenting their hypothesis to begin
with the earlier process.
It may happen, once in a while, that two stars will collide. If
the collision is a grazing one, they say, a spiral nebula will
be formed. However, a fairly close approach of two stars will
occur in vastly greater frequency and the effect of this
approach will also be to form a spiral nebula or two such
nebulae. The authors recall that our Sun is constantly ejecting
materials to a considerable height to form the prominences, and
that the attractions of a great star passing fairly close to
our solar system would assist this process of expulsion of
matter from the Sun. A great outbreak or ejection of matter
would occur not only on the side of our Sun turned toward the
disturbing body, but on the opposite side as well, for the same
reason that tides in our oceans are raised on the side opposite
the Moon as well as on the side toward the Moon. As the Sun and
disturbing star proceeded in their orbits, the stream of matter
leaving our Sun on the side of the disturbing body would try to
follow the other star; and the stream of matter leaving the
other side of the Sun would shoot out in curves essentially
symmetrical with those in the first stream. As the disturbing
star approached and receded the paths taken by the ejected
matter would be successively along curves such as are
represented by the dotted lines in Fig. 28. At any given moment
the ejected matter would lie on the two heavy lines. The matter
would not be moving along the heavy lines, but nearly at right
angles to them, in the directions that the lighter curves are
pointing. As the ejections would not be continuous, but on the
contrary intermittent, because of violent pulsations of the
Sun's body, there would be irregularities in the two spiral
streamers. The materials drawn out of the Sun would revolve
around it in elliptic orbits after the disturbing body had
passed beyond the distance of effective disturbance, as
illustrated in Fig. 29. The orbits of the different masses
would have different sizes and different eccentricities. There
would also be a wide distribution of finely-divided material
between the main branches of the spiral. All of the widespread
gaseous matter, hot when it left the Sun, would soon become
cold, by expansion and radiation; and only the massive nuclei
would remain gaseous and hot.
I see no reason to question the efficiency of this ingenious
explanation of the origin of a spiral nebula: the close passage
of two massive stars could, in my opinion, produce an effect
resembling a spiral nebula, quite in accordance with Moulton's
test calculations upon the subject. Some of the spirals have
possibly been formed in this way (see Fig. 30); but that the
tens of thousands of spirals known to exist in the sky have
actually been produced in this manner is another question, and
one which, in my opinion, is open to grave doubt. But to this
point we shall return later.
There are marked advantages in starting the evolution of the
solar system from a spiral nebula, aside from the fact that
spirals are abundant, and therefore represent a standard
product of development. The material is thinly and very
irregularly distributed in a plane passing through the Sun, and
the motions around the Sun are all in the same direction. The
great difficulty in the Laplace hypothesis, as to the constancy
of the moment of momentum, is here eliminated. There are
well-defined condensations of nuclei at quite different
distances from the Sun. According to this hypothesis the
principal nuclei are the beginnings of the future planets. They
draw into themselves the materials with which they come in
contact by virtue of the crossings of the orbits of various
sizes and various eccentricities. The growth of the planets is
gradual, for the sweeping up and combining process must be
excessively slow. The satellites are started from those smaller
nuclei which happen to be moving with just the right speeds not
to escape entirely the attractions of the principal nuclei, nor
to fall into them. The planes of the planetary orbits and, in
general, the planes of the satellite orbits should agree quite
closely with each other, but they could differ and should
differ from that of the Sun's equator.