toxins or to the gradual destruction of substances required to keep
up youthful vigor? If the latter, the natural duration of life would
be the time necessary to complete a series of chemical reactions that
would produce enough of the toxins to kill. Now, the period necessary
to complete a chemical reaction diminishes rapidly when the temperature
is raised, and increases when it is lowered. This time is doubled
or trebled when the temperature is lowered by 10° C. The influence
of temperature on the rate of these processes seems typical. If the
duration of life, then, is the time required for the completion of
certain chemical reactions in the body, we should expect it to be
doubled or trebled when we lower the temperature. We can test this
only where, as in our flies, infection is avoided. Northrop put their
fresh eggs on sterilized yeast at a temperature of 0.2° C., and the
higher temperatures selected were 5°, 10°, and 25°. All the flies died
at nearly the same time when kept in the same temperature. The total
average duration of life was 2½ days at 30° C., when nearly all of them
died. At 10° C. it was 177 days. Thus heat accelerates all chemical
action, and here we have the duration of life increased from 200 to 300
per cent. In man the body temperature is constant, for example, 35.5°
C. whether in the tropics or the Arctic regions. If we could reduce our
temperature, we might live as long as Methuselah. If we could keep the
body temperature at 7.5° C. and follow the above ratio, we should live
about 27 times 70 or about 1,900 years. Thus the duration of life seems
to be the time required for the completion of a chemical reaction or a
series of them. The latter may be the gradual accumulation of harmful
products or the destruction of substances required for sustaining
youth. Not only are unicellular organisms immortal and the life of all
their successive generations a continuum, but a bit of cancer tumor
can be transplanted to other individuals and there grow larger, and
a bit from this second individual transferred to a third, and so on
indefinitely; so that the same cancer cell continues to live on in
successive transplantations throughout many individual lives. It has
thus outlived many times the natural life of the mouse. Indeed, it
seems to be able to live on indefinitely and Carrel has shown that this
is true of other normal cells. Thus death may not be at all inherent in
the individual cell but only be the fate of more complicated organisms
in which the different types of structure depend on each other. Certain
cells are able to produce substances that slowly become harmful to some
vital organ or center and its collapse brings death to the whole.
In man there is no sharp limit between youth and maturity unless it
be marked by puberty, but in lower forms of life it is demarcated
by a metamorphosis. The tadpole, for example, becomes a frog in the
third or fourth month of its life and this process can be accelerated
by feeding the creature with thyroid, no matter from what animal.
Gudernatsch was able to make frogs no larger than a fly. Allen showed
that the tadpole with the thyroid removed can never become a frog,
although it may live long and continue to grow larger than the usual
tadpole; but if such aged tadpoles are fed with thyroid they promptly
become frogs. Salamanders metamorphose by merely throwing off the gills
and changing the skin and tail, and the Mexican axoloti maintains the
tadpole form through life; but even it, when fed with thyroid, promptly
metamorphoses. Schwingle induced metamorphosis in tadpoles by feeding
them with a trace of inorganic iodine. Thus the duration of the tadpole
stage seems to be the time required to secure a certain compound
containing iodine. Insects hatched as maggots will become chrysalides
and then flies, but if thyroid is fed to the maggot it accelerates
the metamorphosis, although we do not know whether it is due to the
accumulation or formation of definite compounds.
Loeb sought to determine whether the duration of the maggot in the
larval stage could be due to temperature and he found that this had
effects similar to those described above. The larval period lasted 5.8
days at 25° C. and 17.8 days at 15°. The total duration of life was
38.5 days at 25° and 123.96 at 15°, both ratios being 1 to 3. Thus the
influence of temperature upon the larval period was like that which it
exerted on adult life. The same effect he found in salamanders, all of
which suggested to him the conclusion that the duration of life and
of the larval period is really the time required for the completion
of certain chemical reactions. The cessation of respiration, which
means death, and alterations in circulation, which mean metamorphosis
or the death of youth, are critical periods and perhaps both points
are reached when a certain toxin is formed in sufficient quantity or
when a necessary substance is destroyed or reduced. Thus a shortened
youth can, in amphibians, be prolonged by modifying the temperature
or offering the specific substance that causes metamorphosis, namely,
iodine or thyroid. There is no end to the substances capable of
hastening death; shall we ever find one that can prolong life?[176]
Pearl’s experiments on the fruit fly[177] show that where long- and
short-lived strains are mixed, the first generation they produce is
longer-lived than either parent and that for subsequent generations
Mendelian laws hold even for longevity, so that there is increased
vigor in the hybrid generation due to the mingling of germ plasms that
are different. As to bacterial invasion, the stability and resistance
of the organism is also a factor, but by rearing insects kept free from
all such invasion it appears that “bacteria play but an essentially
accidental rôle in determining the length of the span of life in
comparison with the influence of heredity.” Pearl criticizes the
conclusion of statisticians like Hersch that poverty shortens human
life, despite the fact that this is perhaps the most potent single
environmental factor affecting civilized man to-day. But we have no
real evidence that if the conditions between the rich and poor were
reversed the death rate would also be reversed. The influence of high
temperature, which is known to accelerate all the metabolic processes,
does not interfere with the predominant influence of heredity because
it only accelerates life processes exactly in the same way that it
accelerates chemical activities and the same is more or less true of
the influence of the secretions of the endocrine glands.
Pearl concludes[178] that it has already been demonstrated that cells
from nearly every part of the metazoan soma are potentially immortal,
even in the case of tumors by transplantation, though of course not yet
for such exceedingly specialized structures as hair and nails. Under
artificial conditions cells from nearly all organs can be made to long
outlive the body from which they are taken, just as grafts from apple
trees may be passed on indefinitely to successive generations. Thus
death is not a necessary inherent consequent of life in even somatic
cells but “potential longevity inheres in most of the different kinds
of cells for the metazoan body except those which are extremely
differentiated for peculiar functions.” The special conditions under
which this occurs are often very complex and differ greatly for
different tissues and animals, and we shall probably know far more
later of the chemico-physical conditions necessary to insure continuous
life, for these studies are new, having begun barely twenty years ago.
The reason that all these essential tissues are not actually immortal
in multicellular animals is that the individual parts do not find in
the body the conditions necessary for their continued existence, each
part being dependent upon other parts. This view differs from Minot’s
that there is a specific inherent lethal process going on within the
cells themselves that causes senescence. Pearl concludes “that these
visible cytological changes are expressive of effects, not causes, and
that they are the effects of the organization of the body as a whole
as a system of mutually dependent parts and not a specific inherent
and inevitable cellular process. Cells in culture _in vitro_ do not
grow old. We see none of the characteristic senescent changes in them.”
Thus it may be inferred that when cells show characteristic senescent
changes it is because they are “reflecting in their morphology and
physiology a consequence of their mutually dependent association in
the body as a whole and not any necessary progressive process inherent
in themselves. Thus senescence is an attribute of the multicellular
body as a whole consequent upon its scheme of morphologic and dynamic
organization.” The lethal process, thus, does not originate in the
cells themselves. “In short, senescence is not a primary attribute of
the physiological economy of cells as such.”
It has long been known, as we have seen, that unicellular organisms
could go on dividing indefinitely and that germ plasm had a potential
mundane immortality; but no one had suspected that highly organized and
differentiated somatic cells, which had lost the power of producing
the whole individual and could only produce cells of their own special
tissue, had this power. Recent experiments, however, indicate that
under certain highly elaborated conditions they, too, can be made to
live and even grow indefinitely and that this growth can not only be
observed but measured under the microscope. Many attempts had been
made by many individuals to grow tissues artificially to see their
development, their functions, and decay, in both health and disease.
This can now be done by taking pieces of living tissue from the body,
for science has never produced a single living cell, and placing it
in artificial media made out of blood plasma especially prepared, for
nutrition for such a bit of tissue deprived of access to the normal
circulation of the blood is the prime condition for such growth.[179]
Indeed, until Carrel, who had long been interested in the regenerative
processes of scars, succeeded in actually causing cells of the
connective tissue to grow after being deprived of the circulation of
the blood, this was supposed to be impossible. Leo Loeb had already
produced artificial growth within and without the body as early as
1907, and in such processes that utilized the body fluid it was found
that the same course was followed as in nature, so that the processes
in such culture media approximated those that followed grafting. In
1907 Harrison gave details of such a process that seemed convincing,
although he worked only on cold-blooded animals, cultivating nerve
fibers from the central system of the frog. Carrel extended this method
to warm-blooded creatures and mammals, studying especially the laws of
regeneration of tissues after surgical wounds.
The method of these remarkable achievements, now often repeated, is to
put tiny bits of living tissue in a plasma of blood serum that will
coagulate. The blood must be deprived of its cells by the centrifugal
process and must generally be taken from the animal for which the
tissue is to be cultivated or, at any rate, generally from the same
species, although this is not without exceptions, for chicken tissue
has been grown in the blood of human beings, dogs, and rabbits; morbid
tissue, perhaps, like cancer, being most indifferent. The tissue is
taken from an etherized subject, with every possible precaution against
bacteria, chilling, or drying, and so liable is it to be killed by
exposure to air that it is best dissected in serum. Both plasma and
tissue are kept in cold storage and the time during which it can be
thus kept varies very greatly with different animals. The bit of tissue
must be very small because only the outer edge can get the nourishment
when deprived of the normal blood circulation, for when the piece of
tissue is large, all but the periphery dies. To see these changes of
form, small bits of tissue are grown on the inside of a coverglass
of a microscope slide that has been overlain with a prepared plasma,
sealed with paraffin and put into an electric incubator provided with a
microscope. The period before growth begins varies but when it occurs,
the microscope shows the direct division of the nuclei and the growth
taking the form either of layers or of radiating chains, depending
on whether epithelial or connective tissue is being developed. Each
tissue, whether normal or morbid, develops very precisely tissue of
its own kind, and sometimes as, for example, with cancerous tissue,
the growth is so rapid that it can be observed with the naked eye.
This, of course, opens an immense field of observation and experiment,
for example, immunity, protection against antibodies, redintegration,
regulation of growth of the whole or parts, and perhaps especially
rejuvenation and senility, to say nothing of the character and the
influence of the secretions from all the glands. The trouble at first
was that the artificial growth was so short-lived; but by changing the
medium often and by frequent washing away of the waste products in a
salt solution, it was found that the life and growth of these isolated
bits of tissue could be very greatly prolonged. It seemed that the
process of decay was due to the inability of tissues to eliminate waste
products. So in 1912 Carrel’s problem was whether these effects could
be overcome.
To solve this problem bits of the heart and blood vessels of a chick
embryo were grown. These growths were immersed in salt solution for a
few minutes and then placed in the new plasma and it was soon found
that thus the tissue could be made to live on indefinitely. Growth is
more rapid the earlier the stage of it and it soon declines; hence
the advantage of using tissue from embryos. But by subjecting these
artificial growths to washings it was found that they were many times
greater at the end than at the commencement of the month, showing that
they do not grow old at all. Thus C. Pozzi says:
The pulsations of a bit of heart which had diminished in number
and intensity or ceased could be revived to a normal state by
washing and passage through a new solution. In a secondary
culture two fragments of heart, separated by a free space, beat
strongly and regularly, the larger fragment 92, the smaller
120 times a minute. For three days the number and intensity
of pulsations of the two parts varied slightly. On the fourth
they diminished considerably in intensity, the large fragment
beating 40, the smaller 90 times. When the culture was washed
and placed in a new medium, the pulsations again became strong,
the larger one 20, the smaller one 60 times a minute. At the
same time, the fragments grew rapidly, and in eight hours they
were united and formed a mass of which all the parts beat
synchronously.
Pozzi again says:
On January 17 the fragment of a chicken heart embryo was placed
in plasma. It grew readily on a thick crown of conjunctive
cells. In three days the pulsations, which were regular and
strong at the beginning, grew feeble and ceased completely,
and this state continued for more than a month. On the 29th of
February, the culture, which had been subjected to fourteen
passages, was dissected and the central film placed in a new
medium. After the fifteenth passage it contracted rhythmically,
with pulsations as strong and frequent as on January 17,
_viz._, from 120 to 130 per minute. During March and April this
fragment of a heart continued to beat from 60 to 120 times per
minute. As the growth of the conjunctive tissue became more
active, it was necessary, before each passage, to extirpate
the new connective tissue formed around the muscle. On April
17 the fragment beat 92 times, agitating all the mass of the
tissue and the neighboring parts of the middle of the culture.
On May 1 the pulsations were feeble and they were given their
thirty-fifth passage. In the manipulation the muscular tissue
was stretched and torn so that the contractions ceased.
Thus experiment seems to establish the fact that even connective
tissue, composed of not the most highly developed but of vigorous
though low-level cells, is immortal. Senility and death result because
in normal conditions the blood does not succeed in removing waste
products. Could science only wash them away in a living organism, life
might be indefinitely prolonged. It is these connective tissues that
give support to the textures that compose the body and that chiefly
make up bone, cartilage, ligaments, and the lymph network, the cells
of which are endowed with special properties of growth and play a
great rôle in rejuvenating injured tissue. All this work, in a sense,
started from Claude Bernard’s principle that the life of an organism is
dependent on the interaction of its cells and the medium in which they
grow. Thus, to understand the process by which the body develops and
why it must yield to decay and death, we must inquire into the cause of
the loss of character of these interactions; and this was impossible
until tissue could be grown outside the body so that the processes
might thus be brought within the range of the microscope and all its
conditions under control. Carrel’s first effort, thus, was directed
toward the way in which the medium affected the life of the cell and in
constituting this medium of plasma from the blood of dogs and chickens
he found that the older the animal from which the blood was taken,
the less rapidly and extensively the tissues grew in it. In the blood
of a relatively old animal the increase became so slight as to be
practically _nil_. These comparative experiments were made, Grandcourt
tells us, with the blood of animals from five months to five years of
age, and there was enormously greater activity on the part of the blood
of growing animals. Thus it would seem that when an animal attains its
size and stops growing, its blood undergoes progressive changes till
it lacks, more and more, the dynamic power of youth. So the problem
was whether the plasma could be given the force of youth so far as
its action on growing cells was concerned and this was accomplished
by mixing it with juices extracted from the embryo. Experiments, too,
were made with a strain of connective tissue cells that had been kept
in artificial life for more than sixteen months. It was divided into
two parts, one of which was grown on adult plasma and the other in a
mixture of two parts, one of plasma and the other of embryonic juice.
In two days the ring of tissue around the second part was three times
as great as that around the first. Some of these tissues, passed
through a salt solution 130 times, doubled their area in forty-eight
hours. Another, washed 57 times, increased in volume fifteen times in
ten days, etc. These rapid growths, however, could not be duplicated in
normal plasma which was then further modified. Thus the different media
have a pretty constant effect upon the rate of growth. Carrel says:
“The special rapidity of the growth of the tissue depends so much on
the composition of the medium that it may become possible to use as a
reagent of the dynamic value of the humors of the organism a strain of
cells adjusted to life _in utero_.” If human connective tissue could
be preserved in the condition of permanent life as the connective
tissue cells of a chicken are preserved, the value of the plasma of an
individual might be approximated by the cultivation in it of a group of
these cells and by the observation of the rate of their multiplication.
Such observations do suggest some indication of certain values of the
blood of an organism and may give us some clue to old age.
Thus in the course of development the activity of the tissue is apt to
vary in the body as a whole and in its parts. It therefore became a
question whether each particular condition was permanent or whether the
dynamics of the cell changes through the action of the medium upon it.
To determine this, several bits of tissue, each having its own dynamic
power, were cultivated in media exactly alike and differences in the
character of the growth were noted. Then the influence of the medium
began to tell. Measurements of the changes undergone on the part, in
turn of a fast- and slow-growing tissue, showed that the former had
lowered its activity one-half in forty-eight hours, while the latter
had multiplied its activity by six. This process continued until the
level of uniformity was reached, when the conditions of growth remained
equal in all cases. Thus it appears that though, in the beginning,
certain substances that the tissues had accumulated had the effect of
accelerating or retarding its activity in the medium, yet in time the
latter overcame these conditions and growth was brought under the laws
of its own special mechanism. Thus the sum of the investigations on the
influence of the medium on cells is that it may not only change the
dynamic possibilities of the tissue but the character of the change
may be regulated by a carefully considered modification of the medium
(Grandcourt).
All this work involves the theory that the cells make such demands upon
the nutrition supplied by the medium that they deplete it and then
become indirect means of introducing into the life process a chemically
destructive activity (catabolism). The result is a gradual slowing down
of cell growth, which is progressive aging and death. A very analogous
course was that followed in the earlier artificial cultivations. The
tissues lived a short span of days and then died. But the process of
degeneration could be obviated by salt solutions and other processes so
that tissues now grow _in vitro_ for a year and a half and may continue
to multiply faster than those of the embryo. Thus for such tissues
senility does not exist and the question naturally arises whether we
can ever hope to accomplish anything of this sort inside the body.
Carrel in 1914 reported a strain of connective tissue that had
undergone 358 passages and had then reached the twenty-eighth month
of its life _in vitro_. It was detached from the heart of a chick
embryo seven days of age, which pulsated for 104 days and gave rise to
a large number of connective tissue cells. These multiplied actively
for the first two years, a great many cultures having been derived
from this strain every week. The fragment of the tissue usually
doubled in forty-eight hours, though rapidity of growth was subject
to fluctuations. One striking result is seen by comparing the amount
of tissue produced by a given culture in forty-eight hours this year
with that produced in the same tissue by the same strain of cells a
year before. This shows that the activity of the strain had increased,
although this might, of course, be due to improvement of technic
or possibly to a progressive adaptation to life _in vitro_. Carrel
says: “Thus it is conclusively shown that the proliferating power
of the strain has in no wise diminished. During the third year of
independent life, the connective tissue shows greater activity than at
the beginning of the period and is no longer subject to the influence
of time. If we exclude accident, the connective tissue cells, like
infusoria, may proliferate indefinitely.” In the latest report at hand
one of these cultures had been kept alive and growing thus for seven
and a half years.
* * * * *
The original and indefatigable American-Frenchman, C. E. Brown-Séquard
(1817–1894) who in 1878 succeeded Claude Bernard in the chair of
experimental medicine in the _Collège de France_, was one of the
first experimental physiologists to study the functions of glands and
to realize the importance of their secretions. After investigating
the suprarenals in animals as early as 1869 and finding that their
removal always caused death, he returned to this subject twenty
years later to investigate the testicular fluids which, discharged
into the blood, “exalted the power of the nervous system and kept up
the vital energies.” He even injected the fluids extracted from the
testes of animals into his own system hypodermically, with results
that he thought distinctly beneficial to himself and says that he “at
the age of seventy recovered the force and energy of youth, with
manifestations unknown for a number of years.” He thus believed that
he had discovered a new therapeutic agent of great rejuvenating power.
Berthelot says, “The subject required delicate manipulation, not only
because of the extraordinary precautions required for this kind of
investigation but of charlatanism, always ready to possess itself of
new curative procedures. He did not protest against the abuses by which
his name was used to cover industrial enterprises.” He persisted in
his idea, and he, more than anyone else, should be called the founder
of opotherapy or treatment by extracts from organs. His name will
always have a prominent place in the history of endocrinology or the
science that deals with the glands that secrete inwardly, a subject
that already has a vast and rapidly growing literature, with an
essentially new body of facts and insights and, at its present stage
of development, yet far more precious hopes and expectations of great
discoveries just ahead.
Some of the many commercial products of testicular juices, so
very difficult to prepare in a form that can be preserved, were
for many years widely used and the best known of these, Pohl’s
spermine preparations, are still more or less in demand. But despite
Brown-Séquard’s enthusiastic belief in his age-deferring cure, it
lapsed from general attention, partly because the initial expectations
were too high, until a very few years ago when the problems it had
suggested were approached in a new way by a few investigators whose
results have not only a high value in themselves but give promise
of yet more important and definite subsequent discoveries--and that
despite the conservatism and criticism that all efforts to deal
scientifically and fundamentally with human sex problems always
encounter.
Professor Eugene Steinach, who founded a laboratory of comparative
physiology at Prague and was later made director of the biological
institute at Vienna, continued to work there until his institute, for
which Roux and others have solicited contributions from men of science,
to have it opened again, was closed by the war. He began to publish his
epoch-making results in 1910. In spring frogs brought to his laboratory
he found 8 per cent impotent and also that testicular injection from
normal frogs seemed to restore or intensify the embracement impulse and
the strength of the forelegs.[180] The effect lasted, however, only a
few days. Nevertheless he suggests that in borderline cases it might
permanently restore fertility. The same process in castrated frogs
showed the same effect, only in much less degree, and the injection of
substance from the cerebro-spinal centers of these activities seemed to
have a certain but very slight effect upon the sex nature.
When ovaries and testes were transferred in guinea pigs a few days
old, he found, in general, that through the influences of the
hormones from these glands the character of each sex underwent “slow
but radical transformation over toward the other.”[181] In the one
case the male organ atrophied and the breasts were developed, with a
disposition to nurse, the hair became finer, the method of growth was
transformed into that of the other sex; and the converse occurred when
the transplantation was in the reverse direction. The change was thus
both morphological and functional and Steinach believes that there is
a distinct antagonism of the sex hormones due to transplantation of a
heterological gland and that this is not due to biochemical differences
of blood but to a distinct antagonism between male and female
hormones, which have a sex specificity that is the main factor in
directing growth. He distinguishes between the specific sex influence
and the antagonism that brings about heterological sex signs, which
favor the development of other pubertal glands and control growth, even
to the dimensions of the skeleton, both stimulating and inhibiting it.
The transplantation can be so effected that the glands of both sexes,
in a sense, inhibit each other, so that something like experimental
hermaphroditism can be caused. These changes last sometimes through
life and occasionally there may be periodic milk secretions in males.
Each element checks and may throw the other out of function.
In a later article[182] Steinach published results of experiments upon
the exchange of sex glands in other animals between the different
sexes and found that the female masculated by being given the testes
of her brother followed more or less his development rather than her
own, almost equaling him in growth, weight, and robustness. This
Steinach calls hyper-masculinization and a degree of this follows
the development of the glands after transplantation, which the
microscope showed was attended by real intussusception. He also showed
hyper-feminization, so that we have a change of the ovaries into
hypertrophic but analogous pubertal glands, with corresponding change
of traits, dependent upon the degree of success or completeness of the
operation. Thus he thinks, too, we can explain somatic and psychic
precocity by the hypertrophy of these glands. In another article[183]
the author emphasizes the great variability in the development of sex,
both as to size of organs and their functions in different individuals
and believes that besides environment, heredity, race, etc., climate
has a great deal to do with it. He finds that in warm countries the
advent of sex maturity is somewhat earlier in all its aspects, although
there is some suggestion that these accelerations may be connected
with the development of other secondary traits. Experiments made with
animals in artificial climates point to the same result and changes
in this direction are observed in animals accustomed to cold that are
transported to warm climates.
Interesting as these experiments on the interchange of primary
and secondary sexual qualities are, they were, for Steinach, only
preliminary to what chiefly concerns us here, namely, his studies of
rejuvenation[184] and his problem was to see whether by his operations
he could shed light upon the problem of whether age is a condition
we are defenseless against, like an incurable disease, or senescence
can, at least within certain modest limits, be influenced. He says his
experiments have decided in favor of the latter alternative. He had
first to determine whether orthoplastic, homoplastic, or a combination
of both methods was the best. The former was chosen because it was
quickest and easiest and independent of earlier implantation material,
especially with men. And so, with his colleague, Lichtenstern, various
operations were performed, of which three type cases are as follows:
Case 1. Man of 44, lean, weak, wrinkled, incapable of
physical work by reason of easy fatigue. Libido failing for
years and almost extinct, testicular pains, and double-sided
hydrocele. With local anesthesia the typical Winkelmann
operation was performed. On both sides there was ligature of
the vas deferens between the testicle and the epididymis. The
cure took a week and the patient was soon discharged. A few
weeks witnessed a striking change. He increased in weight,
the wrinkles almost vanished, and in five months he had won
back muscular power and become a hard worker, carrying heavy
burdens. “Libido and potence returned with great intensity.”
The upper part of the thigh grew hairy and both hair and beard
increased so that he had to shave more often. Improvement
continued during the year and a half in which he was under
observation and he seemed in every way a vigorous and young man.
Case 2. Man of 71, of large business, who came to the hospital
with an abscess in the left testicle with septic signs--chills,
high temperature, etc.--so that it was necessary to remove the
source of maturation _in toto_. At the same time the right,
sound testicle was subjected to ligature of the passage from
the epididymis to the vas deferens. In twenty-four hours the
patient lost his fever and in three weeks left the hospital.
Quite apart from the acute symptoms, this patient had for
years suffered marked signs of age, especially calcification
phenomena--dizziness, shortness of breath, weakness of
heart, great fatigue, tremors, etc., with libido extinct for
eight years. Within a few months a marked change occurred. A
feeling of masculinity returned and in nine months the patient
described his own condition in a letter in which he says in
substance that, to his great surprise, certain nocturnal
phenomena had recurred, his appetite was so great that for a
long time it was difficult for him to satisfy it, instead of
previous depression he found himself again full of the joy of
life and considered himself very elastic for his age, while his
friends often remarked the great change that had taken place
and could not believe he was seventy-one. He suffers little
from fatigue, calcification and dizziness have ceased, he can
think clearly, had to go to the barber more often, and all his
functions have greatly improved.
Case 3. This was a wholesale merchant of 66 who for some
five years had shown senile symptoms, such as difficulty of
respiration and in thinking, weak memory and also muscles, and
libido almost gone. In this case there was rapid prostatism
and catheterization, also emaciation, and occasionally more
pronounced psychic disturbances. The first operation on this
case was prostatomy but this did not arrest loss of weight or
increasing weakness. Then there was ligature of the vas near
its entrance into the epididymis on both sides, which was
followed by a very rapid recovery, with improvement of nearly
all symptoms.
Thus the author thinks that in fighting old age orthoplasty is by far
the best method, and to the objection that these cases are not true
psychic senescence but only symptoms of intercurrent disease he replies
that this only gave occasion for the operation and that the disease
itself was the result of age. Thus, in general, he concludes that for
advanced senescence the ligature of the vas, as above, gives the most
remarkable results, and that for those before the senium also it may
often work very favorably. The same is true of premature old age, the
advent of which has immense individual variations.
As to checking the advance of old age in women, Steinach is not yet
ready to make any positive report, but in view of what has already
been done with animals he thinks a good prognosis can be made and that
the best method is by implantation of young ovarian material. The
difficulty of this orthoplastic process is found only in the dependence
upon the material of implantation, which is very difficult to secure.
The effort is directed in all such cases to the influence of the aging
ovaries, whether operative by orthoplastic transplantation or by the
use of Roentgen rays. The former, on account of the earlier involution
of ovaries, is confined within certain limits to women. The phenomena
of fatigue, etc., have been removed by this method, which has been so
successful that improvement has been noticed by friends.
In Steinach’s experiments with rats, which pass through the life
stages so rapidly, he used the method of transplantation of testicular
glands furnished by three-months-old individuals and this grafting
need not necessarily be _in situ_ but in various parts of the body.
If intussusception took place, as it generally did if the operation
was well performed, the change here was generally marked within two
weeks, as his photographs show. More or less of Steinach’s work has
been confirmed, Ebstein tells us, by other observers who have shown
that not only in rats but in guinea pigs the transfer of ovaries and
testes between the sexes makes the male, to some extent, become female,
and _vice versa_. Sex differences, Steinach thinks, do not result
from anatomical differences in the organs transferred but are due to
functions residing in certain cells, especially those of Leydig or
Lutein. It is their secretions that determine sex characteristics.
Indeed, they are really glands and vitality and vigor depend upon
their state. Youth is the freshening up of these glands. No one has
recognized more clearly than Steinach that there is a false old age
that has been, in a sense, imposed by civilization upon elderly people
and given them a rôle they have more or less passively accepted, just
as in the same way there are spurious forms of other diseases. Some of
Steinach’s critics have suggested that all he has done is to throw off
these artificial inhibitions and give old age the true character nature
intended it to have. But even if this criticism has any weight against
his conclusions respecting old age in man, it certainly cannot apply
to his studies of senescent animals, for in them the traits of old age
were unmistakable, as not only photographs but, far more, activities
showed. They certainly do seem to be really rejuvenated and not merely
to be laying aside a sham old age.
Of the half-dozen or more expert opinions upon Steinach’s work nearly
all have been by his own countrymen and by far the most exhaustive and,
on the whole, highly favorable is that of Paul Kammerer.[185] For a
very condensed account of it in English see A. Granet’s résumé[186] in
which he says (1) that Steinach’s work is based on a new conception
of the puberty gland as the internal secretory portion of the gonads.
This consists of the interstitial cells in the male and of the lutein
cells in the female. (2) Steinach began by studying animals with a
protracted rutting period in alternating stages of development of
the interstitial gland and the generative gland proper. He found a
periodical hyperdevelopment in the evolution of every individual,
the interstitial gland predominating in infancy and attaining its
maximum development at puberty and adolescence, when growth and vital
energy are also at their maximum. At this time the generative gland
increases and both the interstitial and generative portions continue
to be about equally active till the climacteric, after which there is
rapid recession of the interstitial gland, and this causes senility,
which is not due to the ultimate using up of all elements but to the
lack of potential stimulus due to degeneration of the interstitial
gland. (3) Steinach used this alternating balance of nature in the
mixed gland by artificially inhibiting the generative portion and
thereby causing compensatory regulation and revival of the interstitial
portion with all its rejuvenating effects and the recession of the
traits of senility. This he accomplished by three methods (_a_) simple
ligation, under local anæsthesia, of the vas deferens. This causes
regression of the generative gland and a compensatory regeneration
of the interstitial portions. A one-sided operation is sufficient in
all cases and has the advantage of preserving in addition the power
of procreation. Of course ligation of the Fallopian tube in the
female does not produce this result. (_b_) Repeated mild exposure of
the gonads to the X-ray is a slower but apparently just as effective
a means of obtaining the same result for both ovaries and testes.
And lastly, (_c_) the effects of rejuvenation may be experimentally
produced by transplantation in the old of the respective gonads of
the young animal of the same species. For years Steinach bred and
reared healthy generations of laboratory animals and studied their
dispositions, habits, physical and psychic traits, until he has become
unprecedentedly expert in diagnosing age, to say nothing of sex. The
increased resistance to disease and the actual prolongation of life of
the operated animals he estimates at about 25 per cent but after a time
senescence sets in again.
For women in the climacteric the X-ray method is, by general consent,
best. But Steinach contends that increased well-being and capacity
thus caused are really due to regeneration of the interstitial ovarian
structures. General debility and climacteric metrorrhagias are
distinctly helped by this method because the interstitial portion of
the ovary is not affected by the X-ray whereas the colloidal-albuminoid
precipitation occurs in the cells of the Graafian follicles, which
are radio-sensitive, the same as the metaplastic cells. The affected
cells disappear by autolysis. Menopause sets in and the interstitial
portion alone whose hormones produce the rejuvenating effect remains
functioning. The effects of transplantation, too, are the same and the
shrinking of the transplanted gland seems due to atrophy and should not
prevent rejuvenating effects.
E. Payr[187] calls attention to the fact that Steinach’s puberty
glands, which correspond to the Leydig cells, are those that secrete
internally and that it is these that act so powerfully upon secondary
sex qualities and bring what often appears to be a renewal of youth.
His operation is especially indicated in the case of subjects with
healthy internal organs who are growing prematurely old and who give
evidence of loss of function of secondary sexual characteristics.
G. F. Lydston[188] describes nine cases of men with atrophied testes,
injured, or removed, which were replaced _in situ_ surgically by those
from the bodies of boys recently dead. The glands from the boys were
removed within a few hours after death and generally subjected to cold
storage for some hours and then ingrafted upon the older patient. The
boys from whom they were taken were healthy boys who had suffered
sudden or violent death and there might be an interval of many hours
not only between the death and the removal but between the latter
and the implantation. In all these cases Lydston reports more or
less improvement by the operation, which in a few cases was marked.
The transplanted glands atrophy and disappear more rapidly when the
recipient has more or less well developed testes of his own. Apparently
permanent local results were best obtained in those cases in which the
patient had very little gland tissue. Lydston thinks that there may
be a sort of parasitic action of the patient’s own glands upon the
transplanted ones. His own organs probably contribute the nutritive
pabulum otherwise available for the implanted ones but the therapeutic
results are obtained and sustained even when the implanted gland
eventually disappears. He thinks that the notable result obtained by
Dr. I. L. Stanley, where the glands from a Negro hanged for murder were
implanted in the scrotum of a white moron, apparently with remarkable
results, suggests that atrophy may take place more slowly when the
donor is of the same race as the recipient. The author doubts whether
there is much advantage in anastomosis as to either betterment of
nutrition or preservation of the spermogenetic function. He thinks “we
run more risk of failure of the implant from the greater traumatization
of the tissue necessary for anastomosis.” He thinks, too, that the
spermogenetic epithelium of the testes degenerates in all cases rather
promptly.[189]
In his book, _Impotence, Sterility and Sex Gland Implantation_ (1917),
which seems somewhat ill-digested, Lydston claims priority on eight
points and formulates twenty-one conclusions. It seems to me that
he has not sufficiently assimilated the best European work in this
field or profited as much as he might have done by the far greater
refinements of technique of Steinach; while such results as he claims
are, as he himself admits, always wide open to criticism.
* * * * *
Serge Voronoff, like Metchnikoff, combines research with humanism
and gives free rein to his idealism. He is professor in the medical
school of the _Collège de France_ and deals with old age and death
from the standpoint of endocrinology or the study of the glands of
internal secretion. Accepting Weismann’s doctrine of the continuity
of germ plasm, he says that the nameless and ever unassuaged horror
that everybody really feels for death is “because an intimate memory
of our immortality” survives or because we recollect creation’s first
intention as expressed in plasmal immortality. Man has inherited
this longing from the deathless unicellular creatures from which he
descended not only in the form of quests for elixirs of life here but
in all his manifold beliefs of a life beyond the grave, at the same
time for this life accepting the gospel of renunciation to death as
something inevitable. The ghastly thought of death not only clouds all
our life but predisposes even most scientists to think that research in
this field cannot be successful.
The background view of the work in Voronoff’s field, roughly stated,
is as follows. Somatic cells, having lost the power to propagate the
whole body, as they develop and multiply become more and more special,
not only in form but in function, until they finally lose the power
of multiplication or of regeneration. These are higher and perform
the most particularized functions. Besides these most individualized
cells, so characteristic of every organ that a cytologist can at once
distinguish cells that form the epithelium, intestines, brain, muscle,
glands, etc., there always remain other far less differentiated or
more primitive cells, chiefly leucocytes or white blood corpuscles
and the connective tissue cells. The former float in the blood and
can pass out through the thin walls of the capillaries into other
tissues. The latter constitute all the firmer supportive framework
of every organ. They are very robust, fecund proletarians and are
largely made up of the former. From birth they wage unceasing war
upon the nobler, more professional and expert, but less independent
cells which have sacrificed most of their cruder, pristine powers for
service to the body corporate. These higher cells represent the extreme
division of labor within our bodies. They are no longer sufficient
unto themselves but each class of them depends upon the work of
others. The low, banal, barbaric but vigorous cells of the conjunctive
tissue, on the other hand, always strive to destroy and to themselves
take the place of the higher cells and it is this process slowly
going on everywhere that constitutes old age and all its processes of
hardening, atrophy, disintegration, etc., for these lower cells cannot
discharge the functions of the higher ones they have supplanted and
hence comes anarchy within the organ or body. We die because nature
tends so strongly to develop the cruder type of cell that makes up the
connective tissue.
Now, secretions of the thyroid gland check this aggression of the
lower upon the higher cells, as is shown in the studies of cretinism,
which is in so many respects nothing but premature old age brought
on because the thyroid fluid, the special function of which was to
retard this process, was not supplied; and when it fails, old age
comes on precipitately and even children often look and act much like
prematurely old men and women. On the other hand, the Metchnikoff
ferments of the large intestine weaken the higher cells and leave them
with less power of resistance, so that they become more easily the
prey of the lower cells of the connective tissue. The enemy, however,
for the endocrinologist is not primarily a microbe entering from
without but a more formidable and subtle foe that springs up within.
The difficulty in meeting the situation is immensely enhanced by the
fact that the cells of the conjunctive tissue are not only useful
but indispensable for the work and the development of every organ at
first and continue to be so as long as they do not transcend this
their original function and trespass outside it. The white corpuscles,
although the source of the connective tissue cells, are themselves our
chief defenders. It is they who attack and devour invading microbes but
they consume not only these but also higher cells that have, by the
action of microbes or otherwise, become debilitated. They are, however,
on the whole, so serviceable that we cannot intervene against them but
only against our more dangerous and insidious enemy, the conjunctive
tissue cells.
Not only the thyroid but yet more the tiny parathyroid glands secrete a
fluid, the absence of which brings convulsions and death. A knowledge
of the function of these glands, no larger than a pinhead, as well
as that of the adrenals or of the far more complex pituitary body
(hypophysis), each lobe of which plays its own particular rôle, has
been nothing less than revolutionary. The effects due either to excess
or deficit of the secretion of these glands, which have been studied
experimentally in animals and observed in man, show that they have
great power even to arrest or accelerate growth itself. It is they
that do much to keep us young or make us old. In a sense they furnish
the power that makes about all the organs do their work efficiently,
as an electric current from a battery may start, or its absence stop,
the most diverse kinds of electric machinery. Thus glands have come to
play a great rôle in physiology, medicine, and even psychology, and
their activities have come to be recognized in very many phenomena both
of health and disease, which till recent years no one had suspected.
Some of these glands contain a relatively small number of cells but
do a vast amount of work and manufacture fluids that no chemist can
duplicate and that seem almost magic in their effects. We owe to them
growth, health, and vitality.
Most important of all, and the chief source of human energy in man, are
the sex glands, which distribute energy to all the sixty trillion cells
of the body, making each carry out the function assigned it. Voronoff
made personal studies of eunuchs in the East and among the many traits
so often mentioned he finds them not only arrested along various lines
of bodily and psychic growth but short-lived and perhaps old before
they are forty. They are often selfish and crafty. Sex glands stimulate
not merely amorousness but all kinds of cerebral and muscular energy,
pouring into the blood a species of vital fluid, and give a sense of
vigor and well-being and plenitude of life, which later vanish when
their source begins to run dry in age. Can this wonderful source of
human energy be placed, in any sense, in man’s control? It has already
been proven that trituration of the sex glands does not produce its
entire product and particularly lacks the active element. Moreover, all
preparations of this liquid change very rapidly and may even become
toxic. This method has passed beyond the stage of ingestion in the
stomach or subcutaneous ingestions.
Voronoff undertook to graft young sex glands themselves into
bodies older than those from which they came and if they lived and
throve in the body of the host, the product they secreted would
be complete and also vital. He says of the testes: “To graft this
gland is to participate at first hand in the work of creation, to
imitate nature in the procedures which she has elaborated in order
to secure the harmonious functioning of our body”[190] (p. 65). He
published his first results in 1912. He then showed a lamb born
of an ewe whose ovaries he had removed, replacing them with the
ovaries of her younger sister. His most important paper was read in
October, 1919, on “Testicular Grafts.” He had been experimenting on
flocks of sheep and goats, grafting the whole gland in twenty-five,
large fragments in fifty-eight, and small ones in thirty-seven
individuals. Transplantation was effected subcutaneously sixty-five
times, in the scrotum itself thirty-two times, and twenty-three
times in the peritoneum. Anastomosis did not follow; nor was it
necessary. Testicular tissue, he thinks, has remarkable aptitude for
transplantation and a microscopist, M. Retterer, shows us with abundant
illustrations just what takes place. The nutrition of the small
fragments was more easily assured than that of the large fragments or
the whole. Sometimes where sex power is restored in old animals so
that they bear young, the parental instinct seems weakened, but the
rejuvenation effects of this process, as his many photographs show, are
marked. The old and debilitated animals become well, lively, vigorous,
and belligerent.
Voronoff is very candid in admitting that his interest and enthusiasm
may cause him unconsciously to overestimate the rejuvenating effects of
his grafts, and he also admits that he does not yet know how long the
beneficial effects will last. That they have done so for two or even
three years is beyond question. He is conscious of the incredulity of
biological experts but reminds them that a society of physicists, when
first shown the phonograph, insisted that it was ventriloquism. He
calls attention to the great difficulties in his field, due not only to
prejudice but to laws that forbid the taking of organs of healthy men
killed by accident. He does not expect surgery will ever remove glands
or even portions of them from the living young to revitalize the old,
in human subjects, although he thinks that perhaps “the restoration of
the vital energy and the productive power of Pasteur may well be worth
the slight pain inflicted on the robust porter.” Most men, however,
would prefer to lose an eye rather than one of these glands, as the
price proposed by a few who offered themselves for this purpose shows.
Voronoff sees a great future possible for glandular transplantation and
grafting between men and animals but shows that this can never be very
effective for man save with apes, to whom he is so much more closely
related, even in the makeup and properties of his blood, than to any
other species. Thus the organ of an ape transplanted to man will find
there nutritive and other conditions very like those it was used to.
Surgery has done much and wonderful grafting in the war, even of bones,
and now man, “the talented ape,” as Huxley called him, is recognizing
his simian ancestry in a new way. A fibula congenitally missing in
a child was successfully transplanted from an ape, and the radiogram
showed complete intussusception, no absorption, and it functioned well.
Voronoff transplanted the thyroid gland of an ape into the neck of a
boy of fourteen, who was lapsing to cretinism, with remarkable results
which he describes in detail and with photographs, although the ape
from which the thyroid was taken died. The transplanted gland was not
merely tolerated and then expelled as a foreign body or resorbed but
the graft seemed to really take and its effects to be permanent and
not temporary, like those due to the ingestion of thyroid tablets. The
boy changed in his habits, his school work improved remarkably, and
the last heard from him was that he was a soldier at the front. Here
the beneficial effects were marked and traced for six years and seemed
to promise permanence. Other grafts from apes for cretinism have been
made, but because chimpanzees, which are best for this purpose, are
very hard to procure in sufficient numbers, this process must always
be limited. Voronoff has, however, made no grafts, even of thyroids,
from parent to child save in one case; and here, although the young
imbecile was nearly twenty when the operation was performed, marked
improvement took place. The ape is, in a sense, however, superior to
man, as represented by the quality of these organs, owing perhaps to a
more robust physical constitution; or it may be due to the fact that
with the first boy the graft was from a young ape and the latter from
his mature mother.
For woman, for whom old age has perhaps even greater terrors than for
man, such restoration has not yet been made. Indeed, ovariotomy has
less effects upon young women than does castration upon man, so that
here we face a new problem that cannot yet be solved. The problem now
is whether we can generalize yet from these special studies, including
bone grafting and the surgery of transplantation of other organs.
Kidney grafting has been successful as yet only on cats and dogs but
opotherapy or the administration of glandular extracts of animals when
our own fail is in its infancy, although it does seem to give promise
of deferring death and increasing the vigor of human life. Indeed, he
thinks that the renewal of worn-out glandular mechanisms by grafting
may even become a commonplace. The vital fluid supplied by these organs
“restores energy in all cells and spreads happiness and a feeling
of well-being and the plenitude of life throughout our organism.”
The idea of controlling this marvelous force and placing it at our
service when the natural sources of our energy begin to dry up with the
advance of age has long haunted the minds of investigators, and Paul
Bert and Ollier decades ago dreamed of a day when old organs might be
set aside like worn-out clothes and replaced by new ones. “Several of
these animals operated upon have exceeded the age limit which animals
of their species generally attain and, instead of showing signs of
decrepitude and senility, they give promise of astonishing vigor.”
Louis Berman, M.D.,[191] tells us that infancy is the epoch of the
thymus, childhood of the pineal, adolescence of whatever gland is
left in control as the result of the life struggle, and senility is
the epoch of gradual endocrine insufficiency. The discovery of the
effects of endocrine secretions he compares with that of radium and
thinks that by control of this function we may be able to modify the
rigidity of Weismann’s dogma and affect heredity itself. He draws a
very long bow and even attempts to characterize important personages
and races according to the predominance of thyroid, pituitary, or
adrenal secretions and sees here the fundamental determinants of human
character and conduct. Well informed and expert as he is in this field,
his views, though bold and interesting, are, it must be admitted, more
or less speculative in the present state of our knowledge, and he
devotes little consideration to old age or to the methods of deferring
it.
If we conceive life as the sum total of all the forces that resist
death and death in its essence as the queller of life, it is to
biology, not to theology or philosophy, that we must look for our most
authoritative and normative ideas of both life and death. We must
examine not only the now very copious data that this science already
supplies but also the instrument that defines, delivers, and interprets
them, namely, the mind, so that psychology must henceforth have a place
here second only to biology in formulating conclusions. Now, psychology
teaches not only that there are certain determining tendencies that
always, in part at least below the threshold of consciousness, direct
the course of thought, slowly build up centers of apperception and
interest, and that must always be reckoned with sooner or later not
only in the treatment of any subject in which their action is involved
but also when almost any scientific laws of nature are formulated, but
also that, quite apart from their primary significance for the field in
which they arose, they have a secondary anagogic value in other fields,
in which they become symbols, often of great efficacy. Only the lower
alchemists sought to evolve gold from baser metals and this quest we
now know was always and everywhere really subordinate to the effort to
evolve the _summum bonum_ in human life. So the modern sciences that
deal with life and death, health and disease, are really directed far
more than they know, even in those researches upon the lower forms
of life and most abnormal processes, by the deeper, determining
motivation to know better and to influence more the conditions of human
life. Thus a truer and larger self-knowledge for man is, in this sense,
their ultimate goal.
In view of this, what psychologist can for a moment doubt that the
old problem which F. W. H. Myers called the most insistent that ever
haunted the mind of man has contributed very much to stimulate interest
in Weismann’s doctrine of the immortality of the germ plasm and for a
wide lay public has given a zest and interest in phenomena that can
hardly be observed at all save through a microscope and by an expert.
If we had an analysis of Weismann’s own consciousness from his first
conception of this idea to its full development we should doubtless
find the same factor. True, we search his writings in vain for any
intimation that he recognized any such influence, but I think there can
be no doubt that had he been a psychologist interested in the sources
of his own motivations and had he left us an autobiography as intimate
as that of Spencer, Wundt, or even Darwin, we should have seen that
he realized that he was only giving a new answer to the oldest of all
culture problems. Of course, no psychoanalyst or geneticist would
claim that Weismann was seeking an _elixir vitæ_ or a new fountain
of youth for himself or for others, but it would be equally extreme,
on the other hand, to deny that in the very use of the concept and
term immortal, as he applied them to germ plasm and protozoa, he was
propounding a new if partial surrogate answer to the problem of a
larger life for man. Indeed, we might go further and suggest that
in his extreme pronouncements against the inheritance of acquired
qualities he gave way to the same basal disposition or diathesis
that made theologians so exiguous in formulating conceptions of the
inviolability of divine decrees.
Another underlying psychic determinant is found in the intense
popular interest in investigations like those of Voronoff, Steinach,
and Carrel, of which the latter is perhaps least conscious while
the former is almost as tinglingly so throughout as Haeckel was of
these older concepts. That highly differentiated and complex somatic
tissues removed from the body and given a more fit medium, and kept
from all products of decomposition, etc., can keep on functioning and
growing for years, better than they had done in the body in which they
originated, neither has nor is ever likely to have any real practical
utility for prolonging or intensifying human life. The fact may have
a certain moral for cleanliness and even for nutrition but we can
never wash out the tissues of the body or keep each of its cells in
an optimum environment. Yet even here the mind finds a faint if, all
things considered, somewhat pathetic element of hope that old age and
death may sometime be deferred.
Nor can we ever hope to ward death off by keeping the tissues of the
body young and growing to the end of life and breaking the law, to
which nearly all species are subject, of attaining their maximum size
long before age and decline set in. It has long been realized that one
of the first signs of the advent of the chronic hereditary diseases in
children is the arrest of growth but man can never, of course, hope to
approximate immortality by attaining gigantic size. Nor can we hope to
advance toward the old idea of macrobiotism by permanently lowering
the temperature within the body, as experimenters show can be done
with great increase of life for certain of its lower forms, especially
those called cold-blooded which take the temperature of the medium in
which they live. And yet here man has a very old instinct, reinforced
by modern hygiene, to avoid excessive heat, an instinct that perhaps
originally impelled him to leave tropic regions and haunt the edge
of retreating glaciers. Nor can we ever expect to rejuvenate man by
bringing about a dedifferentiation of organs or functions because just
this is the price we pay for progress, evolution, and individuation.
But this concept, too, has many prelusive forms in the early
developmental history of human consciousness and it has its own obvious
anagogic meaning. If we follow these trends they lead us, of course,
straight to Pantheism and give us a painful sense of the limitations
inherent in personality itself. As to the conclusion of Loeb, that
life departs with breath because the absence of a fresh supply of
oxygen lets loose dissolutive chemical changes its presence prevented,
the pragmatic layman can only point to the recognition that in a few
generations has become world-wide, of the value of ventilation, deep
breathing, and the adequate oxidation of tissues. This shows that man
felt that life was closely bound up with oxygen long before he could
prove it. So the biological evidence that it is the brain or nervous
system that dies first and determines the death of all the other parts
and functions, if it has any culture correlate, finds it probably
in the hazy quarter truths of the doctrines of the mental healers,
that far more human ills and far more deaths and preventions and
postponements of death than we know are amenable to mind cure because
they are mind-made.
The only practical hope of easement from the hardships of senescence
and for the postponement of death now tenable is that now arising
faintly and tentatively that, some day, some mitigation of the terrors
of old age and death may be found by glandular implantation or perhaps
even by the injection of the secretions of certain glands. We know
that the germinal glands, and especially their products, have a unique
vitality of their own and also that they exert a remarkable and
all-pervasive influence upon all the organs and functions of the body;
and that thyroid extract retards and its absence precipitates all the
processes of aging. The new studies in this field suggest that glands
may be the sovereign masters of life. These studies are yet, however,
in their infancy and it will be, at the best, a long time before we can
know whether they are able to fulfill their promise to the human heart
and to the will to live.
I deem it, however, very significant that contemporaneously with the
discovery and exploitation of endocrine functions, and especially those
of the sex glands, from another field and quite independently have come
the discovery and exploitation of the unconscious and the recognition
that its chief content is sexual. The analogies between these two lines
of advance and their real relation with each other have not yet been
fully recognized, much less wrought out. But already there is promise
of a new and more stimulating rapport between biology and analytic and
genetic psychology. If researches in the former field ever have the
therapeutic value already so abundantly illustrated in the latter, we
shall indeed be fortunate. Just now this seems not probable for a long
time. But the physiological dominance of sex glands and their products,
and the immense rôle played by sex life, especially in man, suggest
that it is in this field that the cure of his most grievous ills must
be sought, just as the oldest and most persistent myths and legends
have so long taught that it was in this field that the so-called fall
of man took place.