of agamic bipartition in Infusoria can terminate in a period of
conjugation; a circumstance which produces in effect a cyclical
alternation between agamic generations and a sex-generation. The very
word cycle is used in the observations of M. Balbiani. M. Maupas
elevated this observation of M. Balbiani to the rank of a method;
using, in order to procure the great number of coitions necessary for
his investigations, the following process. He placed the Infusoria in
water in which he had produced a putrid fermentation. The Infusoria,
thanks to the abundance of the nutriment developed in great numbers.
While thus swarming they were lifted out with a drop of water, which
was kept upon the stage in a moist chamber. The Infusoria there
continued to grow larger and multiply; but by reason of their great
numbers it was not long before they exhausted the food brought with
them in the drop of water. When the last remains of their nutriment had
disappeared they were seen in the majority of cases to seek each other
and to copulate.
According to M. Maupas, it is not solely the weakness produced by a
series of bipartitions, but, in addition to that and more particularly,
the scarcity of food, that excites in the ciliate Infusoria the
conjugal appetite. The epidemics of conjugation of which the authors
speak, are not otherwise explainable. M. Maupas even says, that when
a number of pairs are about to copulate, it is only necessary to give
them food to put an end to their conjugation. Scarcity, that author
further remarks, ought evidently not to modify in any essential the
internal organic state of the Infusoria in question; no more indeed
than the opposed condition, that is, an abundance of rich food (page
403 of his memoir). But in the first case they copulate without any
ado; in the second, they refuse to do so entirely. Rich alimentation
deadens the conjugal appetite; fasting, on the contrary awakens and
excites it. There exists moreover, according to the author last
mentioned, in ciliate Infusoria, a particular period beyond which
fecund coitions cannot take place. It is what he calls the period
of karyogamic maturity. Thus, in _Leucophrys_, for example, fecund
coitions are observed to take place only after the three-hundredth
generation. Before that time the Infusoria may be placed in all
the other conditions favorable to copulation, without being seen
to contract a single union. On the other hand, beyond that time, a
period extends in which numerous coitions are obtained. Although,
indeed, the cyclical alternation of agamic generations and copulations
is indisputable, further researches are still necessary to obtain
a thorough knowledge of the extent of these cycles. It is certain
that their duration varies in the different species, and perhaps,
in conditions as yet imperfectly known, may in any one species be
considerably abridged.
We are now come to the preliminaries of copulation. We have described
them in our work, making use of the observations of Balbiani, Gruber,
and of Engelmann, some of which we found confirmed by Bütschli. M.
Maupas, who has recently again taken up this question, believes he
has discovered in his predecessors, or rather in the observations
of M. Balbiani, grave errors. I shall transcribe the passage in
question: "When a numerous group of Infusoria of the same species are
found in the conditions that determine copulation, these animalcula
abandon themselves to certain movements, and exhibit an agitation
the significance of which has been much exaggerated. Balbiani, who
in fact always seeks analogies with the higher animals, has given
us an animated description of these movements, to which a poetical
imagination has contributed at least as much as exact and scientific
observation. This description has met with a most favorable reception
among certain philosophers and psychologists who have taken up with
it in the belief that they could thereby reveal in microzoans the
rudiments of the instincts and psychic faculties of higher-organized
beings. As there is very much inexactitude and exaggeration in all
that, it is time to calm this enthusiasm and to refer the facts and
their explanation to some more exact criterion." (Page 413.)
I believe it useless to occupy my time in dealing with the aggressive
tone that this author has seen fit to assume towards me, and which
seems to be habitual with him when he criticises the works of people
with whom he does not agree. I shall carefully examine his observations
and seek to derive from them some profit, to the improvement and
correction of my work upon the Psychic Life of Micro-Organisms, if it
is true that I have committed the grave errors of which he speaks.
Besides, the question of the preliminaries of copulation is so
interesting in itself that I have no fear of turning to it a second
time.
It is necessary, here, clearly to distinguish two things: the facts
and their explanations. In that which concerns observed facts, the
errors that M. Maupas endeavors to point out in the descriptions of M.
Balbiani appear to me to be capable of a reduction to a matter of so
little significance—admitting that it comes at all from error—that if
I had not been apprised of it, I should have regarded the researches
of the first author as a confirmation in most details of those of the
second. It is to be observed, in fact, that M. Maupas gives almost the
same description that Balbiani does of the movements of _Paramæcium
aurelia_. "I have followed animals of that species a number of times,"
he says, "during the preparations for copulation. They exhibit at that
moment a very great agitation. They are seen to go and come, rapidly
changing their direction. They approach and throw themselves against
their congeners, halt in front of them, feel them an instant with
their cilia, then leave them, assume the most varied positions, and,
finally, when two individuals equally ready for union chance to meet
each other, they face about by their anterior extremities so that the
two bodies come together and join, with the exception of the posterior
extremities, along their whole extent; the union is thus definitively
effected."
Up to this point, let it be observed, our author's description is but
a paraphrase of that of M. Balbiani, which we have given on page 69 of
our work; and a simple comparison of the two suffices to prove this.
The divergences of fact extend, as it seems to me, to the two following
points only: The duration of the preliminaries, and the existence
of an epidemic of copulation. M. Maupas thinks that the movements
in question never last very long, at the most a quarter of or half
an hour among individuals that have arrived at karyogamic maturity.
Whereas M. Balbiani has observed these same movements last for several
days. I do not know which of these two observations is the more exact;
in fact, I do not think it necessary to choose between them, since
both may be exact, the duration of the phenomenon generally being
dependent upon conditions subject to great change, while M. Maupas
himself remarks that the ciliate Infusoria in the variability of all
their biological phenomena are veritable thermometers of a very great
sensibility. However that may be, whether the movements that precede
copulation in _Paramæcium_ last a quarter of an hour, half an hour,
or several days, that fact does not change their real character. The
second divergence relates to the epidemics of copulation in the case of
_Paramæcium aurelia_; observed by M. Balbiani and denied by M. Maupas.
"All the individuals of a group," says M. Maupas, "are never found
simultaneously in this condition. Hence the tentative preliminaries of
copulation, that fail in their object and end in the individuals going
to seek elsewhere another partner." I confess, I do not understand this
statement, involving, as it does, M. Maupas in a contradiction; for two
pages before this he speaks of the mode of the appearance of copulation
as in the epidemic form. All observers, he says, that have occupied
themselves with this phenomenon, state that it is suddenly developed
in the little aquariums in which the animals are contained, and very
rapidly becomes general (page 41).
To this then the divergences of fact are reduced—a matter entirely
insignificant; and I believe it useless to dwell upon it longer. The
question of interpretation remains. I shall also say a few words with
reference to this, although the disagreement is at bottom not much more
serious.
We have seen, that, according to M. Maupas, the Infusoria do not
seek each other and copulate until after a fast of considerable
duration caused by exhaustion of the store of food in the medium
in which they live. The author concludes from this that scarcity
of food is the sole and real cause of the great agitation in which
they are then seen. "When an infusion thickly populated begins to
get exhausted, the animalcula congregate together, always forming
those whitish cloud-spots that we have described as the prelude
to copulation.... Not until afterwards do the actual movements of
copulation occur, which never last very long." Accordingly, there is
first an agitation produced by hunger, and only in consequence of
that are the preliminaries of copulation brought about. Admitting
this interpretation as exact, which is indeed a question that I
reserve, I conclude that M. Maupas completely accepts the facts of the
preliminaries of copulation, distinguishing them from other phenomena
that precede them. He says, moreover, and these are his own words,
that the sexual impulse does indeed exist in these little creatures.
Unquestionably he is right in adding that this sexual impulse presents
in the ciliate Infusoria manifestations much simpler than in the higher
animals, and that it is otherwise in accord with their simplicity of
organisation. That is evident, and no one I believe has ever maintained
the contrary.
Finally, the author refuses to admit that the sexual manifestations
of the Infusoria can be compared with the phenomena of _rut_.
"Rut," he says, "the external and psychic manifestations of which
we know with any degree of exactitude only in mammals, is a reflex
phenomenon concomitant with and consecutive to the maturation of the
Graafian vesicles. It is therefore an especial phenomenon peculiar
to the females of the highest group of the animal series. Males are
not subject to rut, but are always ready to experience the sexual
excitation whenever they find themselves in contact with females that
are fallen into that condition" (page 414).
Naturalists will certainly read with great astonishment this definition
of rut, which is wholly new and personal to the author. Hitherto the
word rut has not been reserved for mammals; it has been applied to all
classes of animals, even to the lowest, and Duvernoy, for example, has
devoted an article to the rut of zoöphytes.
We now come, following the chronological order of the phenomena, to the
material processes of conjugation, otherwise called fecundation, in the
ciliate Infusoria. It is needless to take up in its entirety a question
that we have already examined, and which will be found treated of at
page 65 of our work. But it is certainly interesting to dwell upon the
general significance of the question of fecundation. It is known that
all ciliate Infusoria, excepting some species such as _Opalina_, a
parasitic infusory of the frog, exhibit in their protoplasm two kinds
of nuclear corpuscles. First a nucleus, a principal nucleus, which the
authors designate by the names endoplast and macronucleus; this element
is in some ways comparable to the nucleus of the cells of tissues.
Besides this the ciliate Infusoria possess a smaller nuclear element
than the former, called by the authors nucleolus, or endoplastule, or
attendant nucleus, or finally micronucleus. This micronucleus comprises
in its evolution the internal phenomena of the process of conjugation.
The principal nucleus plays in the process but an accessory rôle, for
it is a wasted element destined to be replaced by a nucleus of new
formation; when it undergoes more or less complete elimination. The
attendant nucleus passes through a series of complicated modifications
which vary much in detail for each species. First, there are stages of
division destined to prepare the way for the elimination of the used
up corpuscles. But the most important fact is that at a given moment
there exists in the protoplasm of each ciliate Infusory in conjugation,
two corpuscles derived from the nucleus; then an exchange is effected
between the two individuals in copulation; each transmits to the other
one of the corpuscles, which copulates with the remaining corpuscle
left in the interior of the body. These two little nuclei that play
parts so different are, according to M. Maupas, completely identical
with one another and do not show the least difference either in form,
volume, or structure. "In the twelve species in which I have succeeded
in closely studying these organs," says that author, "I have always
seen them act with the most perfect similitude under the influence of
coloring and fixitive re-agents." Nevertheless, in view of the future
condition of these two elements, M. Maupas is led to give them the very
significant names of male pronucleus and female pronucleus. The female
pronucleus is the one that remains immobile in the body of the parent
gamete; while the other, the male, is exchanged and passes into the
body of the other gamete.
In what does the real nature of the copulation of these two pronuclei
consist? Does it consist in a fusion of the elements mentioned, or,
indeed, do the latter preserve their original independence and autonomy
in the midst of the new mixed nucleus, standing in juxtaposition
with and moving in and about one another? This is the question that
M. Maupas immediately proceeded to examine. The recent researches
of M. Ed. Van Beneden upon the internal mechanism of fecundation in
_Ascaris megalocephala_ are well known. We have published in the _Revue
Philosophique_, following M. Balbiani, a résumé of these important
investigations, and we may be permitted to reproduce here a few
passages therefrom; for nothing is more interesting than the evolution
followed by our ideas in that which concerns fecundation.
The notions that were formed of this phenomenon only took definite and
precise shape from the time when the existence of the two elements
of fecundation, the spermatozoön and the ovum, could be established.
It was at first believed that the spermatozoön impregnated the ovum
by the exercise of a purely physical action—an action of contact
and influence. But observation demonstrated that something more took
place, namely, an actual conjugation, a union, a blending of the
spermatozoön and the ovule. A further step was made in 1875, when
it was discovered, in studying the ova of Echinoderms, that but one
single part of the ovule, the germinative vesicle, conjugated with but
one part of the spermatozoön, namely the head, and that since these
two elements have each the value of a nucleus, fecundation consisted
in the conjugation of two nuclei. But there was still an element of
obscurity in this idea, simple as it was. If the nuclei were vesicles
like soap-bubbles they might burst, the one within the other; but
the nucleus contains a great number of differentiated elements, the
chromatic reticulated substance, the nuclear substance, the nucleoli,
etc.: what becomes of all these elements during the conjugation of
the two nuclei? In 1881, Flemming made a new advance in the question.
He determined more precisely the nature of the fusion of the two
pronuclei, establishing that it consisted in the blending of their
chromatic substances. This he observed in the ova of the Echinoderms.
According to the very recent works of M. Van Beneden upon _Ascaris
megalocephala_, the great nematoid of the horse, there is no fusion
whatever between the two pronuclei. They always remain distinct. Each
passes through, separately, all the phases of karyokinesis, when the
fecundated ovum divides. In this connection the recent observations of
M. Balbiani confirm the opinion of Van Beneden, who had been sharply
attacked by Carnoy and Zacharias. First, in each of the two pronuclei
each reticulate substance is observed to present the initial phases
of karyokinesis; the net-works form into a skein that contracts and
thickens; the ribbon-like body thus formed divides into two segments,
which bend so as to form acute-angled crooks or loops. There are thus
produced two loops in the male pronucleus, and two in the female
pronucleus. Then the two male loops approach the two female loops in
a manner such that a sort of star is formed with eight branches turned
towards the periphery of the ovum (nuclear or equatorial disk). Then
the fecundated ovum begins to divide into segments. Now at every new
equatorial stage of the subsequent divisions of the ovum these four
loops are seen to reappear in such a manner that fusion never takes
place between the male element and the female element. Each of the four
primitive chromatic loops divides by longitudinal division into two
secondary loops, whence result two equatorial semi-disks, each formed
of four secondary loops, of which two come from the male pronucleus and
two from the female pronucleus. Each of the two new nuclei contains
therefore a certain number of male and female chromatic loops, and
consequently presents an hermaphroditic constitution.
For Van Beneden, therefore, fecundation consists essentially in the
presence in the ovum of two nuclei, one male and one female. The
conjugation of the two nuclei is a phenomenon of no importance; it
may take place, or it may not. The physiological signification of
fecundation is a process of rejuvenation, in which the ovum replaces
its old male element with a new male element, the spermatozoön.[16]
[16] _Recherches sur la Maturation de l'Œuf, etc. Arch. de
Biol. Vol. iv. 1883. Nouvelles Recherches sur la Fécondation.
Bul. de l'Acad. Roy. des Sciences de Belgique, 3 Série, Vol.
xiv. 1887._
M. Maupas remarks that the pronuclei of the Infusoria by reason
of their complicated structures do not admit of these difficult
investigations. Nevertheless he mentions the fact that these pronuclei
are, in the elements mentioned, composed of two distinct substances,
hyaloplasm and chromatin. He puts forth the opinion that the hyaloplasm
constitutes an accessory portion, and that the chromatin is endowed
with the fecundative properties. Which means that in certain ciliate
Infusoria the male pronucleus at the moment of its migration is
composed solely of chromatin. Finally, M. Maupas arrives at the
conclusion that the supreme end of fecundationis the renovation, the
reconstitution, of a rejuvenated nucleus formed by the copulation
of two fecundative nuclei having distinct origins and of which the
chromatin elements represent the essential part (page 434).
* * * * *
It is now time to return a moment to the theory of Weismann and to see
if it has not been shaken by the new data that we have just placed
before the reader. Accepting the results of the experiments of M.
Maupas, who, as a matter of fact, has arrived at the same conclusions
as M. Balbiani, we are led to the admission that when a ciliate
Infusorian multiplies by agamic division a great number of times, the
offspring that appear after from 50 to 100 bipartitions has not the
same physiological value as its original progenitor; and that agamic
multiplication ends in exhaustion and in natural death. But it must, on
the other hand, be taken into account that this process of senescence
is counteracted by that of conjugation, which consists in a nuclear
renovation; and since the substance, the protoplasm, of the rejuvenated
individual escapes death, a new argument might be found in these last
mentioned facts for the theory of the immortality of Infusoria.
The question is, at bottom, whether the individual after conjugation is
identically the same as before conjugation, or whether it constitutes a
new animal. In that the solution rests. Now, the new element that the
individual acquires by the act of conjugation is the male pronucleus of
its partner. In addition it loses the greater part of its old accessory
nucleus and the whole of its old principal nucleus. In return, by way
of compensation, it preserves the integrity of its protoplasm and of
its other organs. M. Gruber believes that physical identity persists in
spite of these modifications. M. Maupas maintains the contrary.
It seems to us that a question of this character does not admit of
a satisfactory solution, and this opinion will be shared by all
who have considered the idea of physical identity. It is a notion
obscure, uncertain, and full of contradictions. We have formed it
because it answers our practical needs. But it is certainly evident
that it corresponds to no well defined external phenomenon. In fact,
we understand by physical identity the constant reunion of certain
elements in a certain order. If the order of these elements is very
slightly modified, or if a very small number of these elements is
replaced by others, we do not hesitate to say that the physical
identity in question has not been altered by these insignificant
modifications. If, on the other hand, the order has been almost totally
destroyed, if the greater portion of the elements has been renewed, we
should, on the contrary, say that the identity of the thing in question
had been lost in these alterations and that a new object had replaced
the old. Replace a stone in a house and the latter remains the same
house; rebuild the house upon a new plan and with different materials
retaining very little of the first construction, and it is a different
house. But between these two extreme cases there is a whole series of
possible intermediate changes, and we are not able to establish clearly
by any exterior mark the point where physical identity ends. This is a
matter of personal estimation; I might even say of caprice; and all the
discussions raised upon these questions appear to me wholly idle.
I believe, accordingly, that the thesis of Weismann regarding the
immortality of Infusoria eludes a direct refutation. It is neither
confirmed nor overturned by observed facts.
ALFRED BINET.
ON THE MATERIAL RELATIONS OF SEX IN HUMAN SOCIETY.
Much interest is displayed at present in the development of woman,
both as to her personal characteristics, and in her relations to her
surroundings in human society. It is justly said that the civilisation
of a nation may be measured by the degree of humanity displayed by its
men towards its women. This is for the reason that, since women are
the weaker sex, man has only ethical reasons for self-restraint in his
treatment of her. Nowhere is the sex-interest under better ethical
control than in the United States; and it is in this country also that
we hear the most of reforms which are necessary in order that woman
may attain a further development, and assume a higher position in
relation to the state. This being the case, it is extremely important
that the foundation facts, or in other words the necessary natural
conditions, under which the sexes co-operate in society, should be
fully understood. That they are not understood, or that they are
intentionally ignored in some quarters, is evident to any one who reads
the current literature of the subject.
The relation of the male man to his environment involves the usual
struggle for existence more or less active. His _pièce de resistance_
is the mineral and vegetable world and its atmosphere, and his
antagonist is his fellow man. The former generally yields more or less
abundantly to his solicitations. What he gets from his fellow man is
acquired through the necessities of the latter, and the benefit may be
mutual, or it may be all on one side. His best friend may unconsciously
and unintentionally, in the regular order of trade, reduce him to
beggary, or compel him, as an alternative, to emigrate to a distant
land. Such results are more frequent as population increases. To
maintain himself against the destructive forces of nature, such as
cold, heat, rains, tempests, fires, blights, etc., is his necessary
occupation. If he pursue a profession, or if he be in trade, he must
supply the actual needs of his fellow man, and beware that competition
and monopoly do not deprive him of all return for his labor.