Part 11

Only a few years ago Carl Vogt vehemently opposed the opinion of the duckbills being transitional types, and sought to explain their inferior stage of organisation, which is also evidenced in their low blood temperature, as the results of a stunting process (degeneration, so called). They formed a degenerated branch of marsupials, nothing more. Later, the remarkable yet long anticipated fact was revealed by Haacke and Caldwell, 1884, that the duckbills are egg-laying mammals, a character which certainly could not have been acquired through degeneration, but which simply shows that they are closely related to extinct reptilian forms. In one other respect, namely, with regard to their supply of teeth, the process of degeneration must indeed be admitted. On this point, Poulton and Thomas discovered a few years ago that in their early stages they really do possess true teeth, which, however, just as in the case of certain carnivorous cetacea, later completely disappear, and are replaced by a sort of horny teeth. This, however, is really not a true degeneration, but rather a special adaptation, doubtless beneficial to the animal in some way or other; and with as little reason as we may regard birds as a degenerated race in comparison with their progenitors, because they have lost the numerous teeth which these possessed, with just as little reason can we hold that the duckbills, in their general organisation, have suffered any retrogression worth mentioning. On the contrary, the recent investigations of Marsh and Lemoine concerning the mammals of the Jurassic and Cretaceous periods point more and more distinctly to the conclusion, that there existed among these mammals a very large number which possessed the same degree of organisation as the duckbills of to-day, now represented by only a few species; a supposition which the adherents of the theory of evolution made twenty-five years ago. I do not know that the pedigrees of the heroes of Homer have been so well preserved!

In many other directions, however, speculation of late years in Germany has considerably digressed from the facts of experience and from all probability; especially with reference to the questions of propagation, variation, and heredity. Here, first of all, are to be mentioned the works of Weismann, _Ueber die Continuität des Keimplasmas_ (1885), _Die Bedeutung der sexuellen Fortpflanzung für die Selectionstheorie_ (1886), _Der Rückschritt in der Natur_ (1886), _Die Bedeutung der Richtungskörperchen für die Vererbungstheorie_ (1887), _Die Hypothese der Vererbung von Verletzungen_ (1889), and _Ueber Amphimixis_ (1891).

If we revert to the beginnings of this movement we shall find that it is intimately connected with the more exact study of the processes of fecundation as perfected through the researches of Strassburger, the Hertwigs, and other investigators. In connection with the ideas of Nägeli concerning the so-called idioplasm, the notion was reached that the matter determinative of heredity was contained in the nucleoli, and that by the union of the paternal and maternal nucleoli the sum-total of the parental hereditary tendencies is transmitted to the offspring. This view was to a certain degree verified by the experiments of the brothers Hertwig in removing the nucleoli of the eggs of the sea-urchin; the result being that eggs containing the nucleoli alone, furnished, through artificial impregnation, results resembling the female parent, whereas eggs from which the nucleoli had been removed, furnished germs completely corresponding to the traits of the male parent.

Other processes of fecundation, to which we shall soon recur, had since 1876 produced the impression in the minds of a number of naturalists that the germ-material led an independent life in the bodies of organisms, that it possessed only an internal development, and required from the body nothing but nourishment in order to multiply itself, and to develop its internal powers uninfluenced by the various vicissitudes of the body. In the year 1876 Gustav Jaeger in Germany, and Francis Galton, a cousin of Darwin, almost at the same time in England, called attention to the observation made some time previously, that in certain animals, particularly in insects, the development of the egg into the young offspring begins with the withdrawal of a small portion of the germ from the component substance of the embryo, which remains at first unchanged and only later multiplies. This observation was generalised and accepted. At the commencement of every sexual multiplication the germ-substance, after impregnation, is divided into two parts, according to its future purpose; an ontogenetic or personal part, out of which the body is built up, and a phylogenetic or germinal part, which at first is stored up unused in the individual, but later furnishes new germ-cells. This idea led Weismann to his view of the continuity of the germ-plasm, which forms an unbroken line of descent from the first beginnings of the species and which is simply nourished by the organisms in which it has its temporary abode. From this germ-plasm spring _secondarily_ the cells that go to make up the body (soma); but from these soma-cells no new _germ_-cells can originate, and consequently none of its inherent or adscititious qualities are capable of transmission. The somatic cells make up the mortal and perishable forms of life, while the germ-cells alone insure the further existence and immortality of the race.

It is easy to perceive that these views, if they could be maintained, would completely transform the Darwinian theory. Since, if the somatic cells, that is, the body-parts of animals and plants, with all their adaptations to soil and climate, to definite modes of life, etc., are to be deprived of every power to transmit hereditary characters, then the so-called Lamarckian theory, which should really bear the name of Erasmus Darwin, would be deprived of every foundation which it possesses. Neither the increase in strength of the members of the body, acquired by use and practice, nor their weakness created by their non-use could be inherited; and in just as small a degree could changes caused by external influences, bodily injuries, sickness, entail consequences which were inheritable. This being the case, then also all those views would be untenable which seek to explain the important effects of time as the result of the accumulation and augmentation of the minute impressions of the external environment. If the variations which are generated by means of external influences are not capable of transmission, then the direct adaptation must commence at the beginning in the case of every following generation; an accumulation is impossible.

We can observe, however, in every particular case, the complete harmony in which every living being exists with its surroundings and mode of life; and observe in closely related species the most various adaptations to the elements in which they live: climate, food, nay, even to the particular companions with which they associate; with the result that many plants have shaped the structure of their flowers to conform to the physical anatomy of the insect which ordinarily effects their fertilisation, and that animals assume the figure and form of some associate who is safe from hostile assaults, or even completely adopt different modes of life where it is necessary to enter a life-partnership with a strange animal or plant. But, granting that the most widely extended capability of adaptation is a thing of daily experience, there still arises the question how we shall explain this quality, which can only be brought about by slow degrees, without taking into account the factor of heredity in the transmission of acquired qualities. The theory of Weismann attempts this, in that it takes for granted an infinite variability in the germ-formative materials, and guides the new forms and variations thus begotten into the really true path, that is, into the most successful paths, through the process of natural selection (that is, through the survival of the fittest as regards environment and all other things). According to this doctrine, external circumstances have no direct influence whatever upon the variation of species, as Erasmus Darwin, Lamarck, and the founder of the theory of natural selection and all his followers up to that time supposed, but we have to have recourse to a pure theory of natural selection, and call to our aid an, even now, rather obscure phenomenon, occurring in connection with sexual impregnation, which has been called “the expulsion of the polar bodies,” an extrusion of minute qualities of germ-plasm from the germ-cells while in union. By the processes of crossing, which continually recur, a vast number of the most manifold hereditary tendencies are united in the germ-material. Then certain of these are ejected, so that others acquire supremacy; and in this manner the way is opened for the origination of a vast number of possible combinations. In this way the path is clear to a theory of perfect mechanical variability, in which the germ-material has only to transmit the characters which spontaneously arise in it, and yet affords an investigator endowed with any imagination the possibility of understanding the origin of the great variety and final purpose of the world. It is Frohschammer’s “principle of the imagination as the creator of the world” translated into comprehensible formulæ. The simplicity thus reached by the elimination of all direct influences from the external world, has won the adherency of many investigators following in Darwin’s steps, particularly in England; but whilst Wallace, Galton, Ray Lankester, and others have expressed their full assent to it, other and not less eminent authorities, as Herbert Spencer, Haeckel, Fritz Müller, and Virchow, have emphatically rejected it.

The reasons in favor of this assumption are, as is indeed the whole view itself, mainly of a theoretical nature; the arguments of the opposition are divided into philosophical and experiential propositions. The philosophical opposition is mainly based on the fact that, from the very beginning, there is assigned to the germ-material, as it unceasingly continues its existence, an infinite variety of capacities which the external world cannot affect, and that all progress and advancement takes place as the result of the _loss_ of the originally endowed powers and tendencies. On this theory a family of acrobats or race-horses would not acquire their powers through the gradual augmentation by practice of their feats of skill and endurance, but because these powers were originally resident in them, and every factor incompatible with them was gradually eliminated. On the other hand, these views approach in a dangerous degree to the theories of predestination and preformation, the overthrow of which has been justly regarded as one of the greatest advances of science.

Still more important must be considered the objections of empirical science, which up to this time was completely convinced of the heredity of acquired qualities. Popular experience, as well as that of physicians, universally speaks of inherited disease-germs, and in certain cases, particularly in mental diseases, physicians are so thoroughly convinced of their inheritability that the first question put to the relatives of such sufferers usually is whether the disease has ever appeared in the parents or family of the patient. This fact is so deeply grounded in the general belief, that the modern naturalistic school of novelists, the school of Zola, Ibsen, and their associates, are wont to devote their main efforts to the problem of inherited evils. Now the inheritability of certain evil conditions, even though proved, would not by any means be an absolute disproof of Weismann’s theory; for, inclined as much as we may be to derive diseases from mistakes and sins against a natural mode of life, such as colds, drunkenness, dissipation, mental and bodily over-exertion, we yet cannot deny _a priori_ that blastogenic diseases, or diseases originating in the germ-plasm, may exist, which without any doubt would then be transmissible. It also does not lie beyond the realms of possibility that congenital malformations, such as hare-lips, supernumerary fingers, and the defects which show a remarkable disposition to heredity, fall into this category. These blastogenic germs of disease would then, of course, have to be distinguished from the somatogenic diseases (or the diseases produced in the body by external causes), which never could be inherited.

From this point of view the question as to the hereditary consequences of external injuries has given rise to great efforts to prove experimentally the truth of this belief, which has existed for centuries. In almost every part of the globe we meet with the assertion that hornless cattle, such, for example, as are bred in South America, or the tailless cats of the Isle of Man, or other domestic animals with similar deficiencies, are descended from a progenitor which lost its horns or its tail through disease or other mishap. Since now, recently, similar assertions have again been put forward to the effect that tailless cats are found among the descendants of feline progenitors who have been robbed of their posterior ornaments by an act of violence, and these cases have been discussed in connection with the pangenesis theory of Darwin, according to which each part of the body is believed to supply material contributions to the germ-plasm, Weismann determined to institute experiments on this point. He started the breeding of white mice whose tails were regularly cut off, without finding as a result, from among 840 young ones derived from such mutilated progenitors, a single one having a malformation or missing tail. However, even this experiment cannot be regarded as an absolute proof, as it at first view might seem, and the negative result was foreseen by the writer of these lines. It is a clear conclusion that if in the case of many vertebrates, for example, salamanders and lizards, as well as in the case of most invertebrates, missing limbs and tails are renewed in the course of their lifetime, it would indeed be very remarkable if their renewal should not take place, at least in the case of the complete rejuvenation of new birth.

Darwin himself had concluded, from his own experience and that of others, that injuries and similar inflicted acts of violence are the cause of hereditary consequences only in cases where they bring about some long-continued and wasting disease, and thus produce some permanent effect on the bodily constitution. For this reason, especially injuries to main nerve-tracts in parts near the centres are readily accompanied by hereditary consequences, because they interfere with the nutrition of the members supplied by them. Brown-Séquard has observed in a great number of cases of guinea pigs whose nerve-roots he had severed, that the offspring of the animals operated upon developed diseases of the eyes, ears, and other organs which conformed regularly to the character of the operation, and could therefore be predicted; and also noted malformations and deficiencies, amounting even to the complete disappearance of the eye-balls, such as never arise or have been observed in these animals without violent interference. His positive results regarding the hereditability of the evil consequences of disturbing operations have a decided advantage in numbers and scope over the negative results of Weismann; and it is not clear how the belief in the non-hereditability of somatic conditions will accommodate itself to them.

But if conditions of the body produced by such sudden interferences have under certain circumstances entailed hereditary consequences, how much more should we expect this same result from slowly effected constitutional changes, which external influences, working uninterruptedly for hundreds of years, bring about in an organism which has been transported into a new element, into new surroundings, or into a different climate. Not at all infrequently does the coming together and union of two new organisms beget hereditary changes which can be explained only through the direct influence of the one upon the other. Thus, for example, in the case of plants in hot countries which are protected against the assaults of leaf-devouring ants by body-guards of smaller ants, and also in species of quite different families, as, for example, in _Cecropia_ of the order _Euphorbiaceæ_, and in some _Triplaris_ species among the _Polygonaceæ_, we find little chambers, approachable through small openings in the stems, which serve the ants protecting the plants as dwelling and breeding places. Are we to believe now, in regard to this fact, that these plants, so different in their nature, have produced through voluntary variations the stems which contain these openings, or are we to believe we have to deal here with openings acquired through inheritance which originally were bored in the stems by the ants at the most appropriate points? Surely the first conclusion, which would uphold Weismann’s theory, has but a very slight degree of probability in its favor, whilst the latter, which would overthrow his view, is very highly probable. And such examples could be cited in great numbers.

It is also to be remembered that the power of variation is not exhibited solely in sexually created individuals, as it should be according to Weismann’s theory, but frequently also in non-sexual multiplication, where no amphimixis (mingling) occurs. It is well known that the majority of the sporting varieties of our trees, for example, _Fagus sanguinea_, and the so-called weeping varieties, that is, abnormal varieties with pendent twigs, forms with split, spotted, or white leaves, are wont first to appear on single branches of old trees, in which the continuity of the protoplasm unquestionably existed, but no amphimixis or extrusion of the polar bodies took place. It is also the generally received opinion of naturalists that the lowest classes of animal and plant life are universally multiplied by non-sexual means. And if this is so, it is not clear how higher forms which sexually propagate can be derived from them, if the latter have originally to furnish the fundamental conditions of variation. The adherents of Neo-Darwinism will, accordingly, have to furnish many additional facts if they wish to invest their theory with any degree of probability.

CARUS STERNE.

FOOTNOTES:

[16] _Cenogenesis_, from κενός, empty, fruitless (and γένεσις, birth); not from κοινός, common, the derivatives of which are sometimes written “c_e_no.”—ED.

II.

FRANCE.

The study of personality, from the point of view of pathological psychology, has already supplied us with numerous books. M. ALFRED BINET, in his fine work, _Les Altérations de la Personnalité_, has undertaken to present systematically to us these alterations in their entirety, while restricting himself to ascertained results, and avoiding disputed points. He exhibits to us the “dismemberment of the ego” in diseased states, the frequent rupture of that “unity of consciousness” which is the principal attribute of the normal individual.

Clinical observation has established the existence in certain subjects of successive personalities, and in others that of co-existing personalities; the experiences of suggestion have at last allowed of analogous morbid phenomena being provoked, in such a manner that cases may be varied and rendered still more instructive. The simple movements provoked in normal persons in states of distraction, of which many very curious examples may be found in M. Binet’s book, are the recognised mark of a subconsciousness; but it is often possible, under the same conditions and with the same processes, to provoke in a hypnotisable hysteric individual an actual sub-personality, that is to say, to augment the phenomena which attentive observers have long since remarked in every-day life.

It cannot be doubted that, on the one hand, it is possible to produce in an insensible limb a great variety of subconscious actions, and all sorts of reactions; and when they are recorded by the graphic method, it is perceived that with the fingers of his insensible hand, the subject has made movements the form of which varies according to the receiving apparatus (the dynamograph, drum, pencil, etc.). These movements thus exhibit the truly psychological marks of adaptation, and seem to reveal the existence of an intelligence which is other than that of the ego of the subject, and which acts without his assistance and even unknown to him.

On the other hand, numerous experiences of very different kinds show that the subject whose anæsthetic arm, for example, is pricked, can have an idea of the stimulation, although he does not perceive it. He does not feel the prickings, but the excitation calls forth the idea of their number: he counts them as a normal individual would do; “only, in hysterical individuals, the first part of the process occurs in one consciousness, and the second in another.”[17]

It can hardly be denied that these different consciousnesses are distinct; since experience proves that each can have its own perceptions, its own memory, and even a moral character. However, their relative value with respect to each other matters little. We are compelled to consider, with M. Ribot, the ego as a “coördination” of states of consciousness, admitting of infinitely variable groupings. According to the old conception of the ego, the personality, with respect to secondary consciousnesses, was compared to a coachman who had ceased to have control over his horses. This comparison is now insufficient, since it may happen that the coachman falls asleep on the box, and that one of the horses then governs the set, regulating, more or less perfectly, the pace of the others by its own gait. Spiritualists, however, will never consent to put the ego in the place of the coachman. “A stone detached from the complex structure of the personality,” M. Binet now tells us, “can become the starting point of a new structure, which rises rapidly by the side of the old. Whereupon a disaggregation of the psychological elements is produced.” This comparison is certainly more precise and more in accordance with facts.

Moreover, there remains to be explained how the mental compound which constitutes the ego has been constructed from its elements. M. Binet shows, _à propos_ of this question, that the association of ideas is powerless to explain the genesis of personality; associations alone, as proved by the experiences of suggestion, are not sufficient to restore forgotten memories. Neither is memory the sole factor in personality; since, in certain conditions a person may, while preserving the consciousness and the memory of certain of his mental states, nevertheless repudiate these mental states and consider them as foreign to himself.

This question is still an open one. But there exist certainly some grounds for our seeking in the division of consciousness the key to certain psychological facts, like unconscious cerebration. Such a key would be the action of detached consciousnesses and detached memories, that afterwards immediately enter the current of general consciousness. Finally, “it is possible,” as M. Binet says in conclusion, “that consciousness may be the privilege of certain of our psychic acts; it is possible also that it exists everywhere in our organism, and it may be even that it accompanies every manifestation of life.”

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