The weak, untrained brain must have a conclusion. It cannot reserve its decision or render an open verdict. It is completely at sea in the scientific world where the most profound savant is often obliged to say, “I don’t know.” In a crowded courtroom, ninety per cent of the spectators have made up their minds that the prisoner is innocent or guilty before the first witness is called or a line of the evidence has been read. He has a square jaw, or bushy eyebrows, or thick lips, or he shifts uneasily from one foot to the other, any or all which proves to the simpletons back of the rail, that he must be guilty no matter what the crime is, or what the evidence may be. If he has blue eyes and fair hair and mustache, or a pleasant manner, or pretty hands and the onlookers were to decide the matter, they would hardly convict him on his own confession. In England, a judge is not placed on the bench because he “stands in” with a ward boss, but because of his wide scholarship and systematic training, and the reason advanced for this method is, that only a scientific scholar can reserve his opinion until all the evidence is in and then, if the case demands it, render an open verdict.

With the vexed problem of heredity, which has been so much to the fore in science for the last twenty-four years, while many great thinkers have distinctly taken sides, it must be remembered that in many points of great importance, the only possible verdict on the contentions of either side, is one of “not proven.”

But although this controversy has split the evolutionists into two camps, it in no way compromises the evolution theory itself. The controversy is based on the admission of all the parties to it, that evolution is granted, and the question at issue involves only a difference as to how the acknowledged results are accomplished. Evolution is no longer merely a theory, it is an established fact, and is recognized as such by all who live in an intellectual atmosphere belonging to this side of 1859, the year of the publication of the “Origin of Species.”

Neither does the result of this discussion threaten, in any way, the validity of the Darwinian theory of “Natural Selection.” All the disputants are avowed Darwinians, and disagree only as to whether Darwin’s theory is alone sufficient to account for the origin of new species.

Professor Packard, Lamarck’s biographer, and one of his warmest admirers, at the close of his chapter devoted to the denial of “pure” Darwinism says: “We must never forget or under-estimate, however, the inestimable value of the services rendered by Darwin, who by his patience, industry, and rare genius for observation and experiment, and his powers of lucid exposition, convinced the world of the truth of evolution, with the result that it has transformed the philosophy of our day. We are all evolutionists, though we may differ as to the nature of the efficient causes.”

There are now three possible positions. (1) That of the Lamarckians, pure and simple, who maintain that Lamarck’s theory in itself explains all the phenomena, and that Darwin’s principle of selection is not only invalid but superfluous. This school is practically extinct, though Packard often sails to its very edge in his efforts to defend his subject, as is the manner of biographers. (2) The Neo- (New)-Lamarckians who develop Lamarck’s theory and add to it Darwin’s selective principle as of greater, equal, or secondary importance, according as they lean the more strongly to Darwin or Lamarck. This position held the field almost alone, until Weismann fired his opening gun in 1883. He founded (3) the Neo-Darwinian school which repudiates altogether the Lamarckian factor of the hereditary transmission of acquired characters, and maintains that Darwin’s theory is able to dispense with Lamarckian ideas of use and disuse.

As Weismann is the storm center of the controversy we will now examine his theory.

In 1883 Weismann became the pro-Rector of the University of Freiburg and in the hall of the University, in June of that year, he publicly delivered his inaugural lecture “On Heredity.” This lecture is generally regarded as the first broadside in that war which filled with its reverberations the scientific magazines of the world for the next thirteen years. As one writer aptly says, “The warring scientists splashed like irate cuttle-fishes in clouds of their own ink.” About 1896 however, the public grew tired of the never-ending flood of biological lore on what looked to the lay mind like an insoluble problem. The editors, with their fingers on the public pulse, cried, “A plague on both your houses,” and sent the savants to seek in their laboratories the victories denied to their pens.

As a matter of fact however, the coming struggle was foreshadowed in a paper read by Weismann at the meeting of the Association of the German Naturalists at Salzburg, two years earlier, in 1881.

This paper was entitled “The Duration of Life,” and the subject was still further developed in an academic lecture, in 1883, on “Life and Death.” These two biological contributions not only indicated the foundations of Weismann’s theory, but they threw a very brilliant light in certain very dark places. Weismann not only took up, but he solved the hitherto obscure question of the origin of death.

Johannes Muller had, as early as 1840, rejected the prevailing hypothesis which held the death of animals to be due to “the influences of the organic environment, which gradually wear away the life of the individual.” Muller argued that if this were so “the organic energy of an individual would steadily decrease from the beginning.” Everybody knows, however, that in spite of the wear and tear caused by the “environment,” be it organic or inorganic, the volume of life increases, until a certain stage is reached in all animals. But Muller had failed to fill the gap his criticism had created. This problem Weismann solved by analysing the methods of reproduction among animals. These generally speaking are two; sexual, and non-sexual or, as it is sometimes termed, a-sexual. This latter form is the mode that prevails at the bottom of the organic scale—among the protozoa, animals consisting of a single cell. This method has a variety of forms which are classified by Haeckel as (1) self-division; (2) formation of buds; (3) the formation of germ-cells or spores. We shall here deal only with the first, self-division, or fission, which is the most universal of all methods of propagation, being the progress by which the individual cells which compose all the higher animals multiply themselves. This is the method vital to Weismann’s theory and the other two are no more than distinct modifications of fission.

When a Moneron or an Amoeba reaches a certain size, it begins to pinch in the middle like a tightly-laced corset. This increases until the creature divides into two equal halves. Each of these halves becomes a complete individual which continues to thrive until the next division takes place.

What Weismann observed as the most significant thing about this was that in this process and among these unicellular (single celled) organisms there is no such thing as natural death. Accidental death is wholesale in its proportions, but no Moneron ever dies of old age. Astounding as it may seem to the layman, the race-old, world-wide idea that death is “essential to the very nature of life itself” is here totally and indisputably overthrown.

“I pointed out,” says Weismann, in the second lecture and referring to the first “that we could not speak of natural death among unicellular animals, for their growth has no termination which is comparable with death. The origin of new individuals is not connected with the death of the old; but increase by division takes place in such a way that the two parts into which an organism separates are exactly equivalent to one another, and neither of them is older or younger than the other. In this way countless numbers of individuals arise, each of which is as old as the species itself, while each possesses the capability of living on indefinitely, by means of divisions.”

Among the Metazoa, i. e., multicellular or many celled animals, this immortality of the individual disappears. “Here, also,” says Weismann, “reproduction takes place by means of cell-division, but every cell does not possess the power of reproducing the whole organism. The cells of the organism are differentiated into two essentially different groups, the reproductive cells—ova or spermatozoa—and the somatic cells, or cells of the body. The immortality of the unicellular organism has passed over to the former—the reproductive cells—the others must die, and since the body of the individual is chiefly composed of them, it must die also.”

And so death came into the world, not by sin, as the Genesis legend reports, but through sex; a most astonishing conclusion, it may be, but one from which there is apparently no escape. Immortality still remains, it is true, but it is not the immortality of the conscious self. Positive science, nothwithstanding all its glorious gifts, has dealt a terrible blow to those gorgeous dreams of primitive men and modern mystics; those hopes and longings which have sustained millions of our race in hours of supreme sorrow; a blow which not even the bravest has been able to receive without flinching. The only immortality of which science has any surety is that of these unconscious single cells, which make possible the reproduction of the species.

Weismann, then, divides the cells which compose the bodies of the higher animals, including man, into two distinct kinds; the somatic, or body cells and the germ, or reproductive cells. These germ cells are, so to speak, batteries in which are stored a substance which Weismann calls germ-plasm. A minutely small portion of this germ-plasm from an individual of one sex, mixed with a similar portion from an individual of the other will produce a new individual. But—and here comes the keystone of Weismann’s arch—only a portion of the mixed germ-plasm is used up in the composition of the new individual; the rest is stored away in the germ-cells of the new individual for further reproduction when the time arrives. The only relation that this reserved germ-plasm has with the body cells of the new individual is that it is provided by them with room and board.

Thus, according to Weismann, from generation to generation, there is an unbroken stream of germ-plasm, and this constitutes his celebrated theory of “The Continuity of Germ-Plasm.” Granted this theory as a premise, and Weismann’s conclusions cannot be gainsaid. This germ-plasm being the sole “carrier of heredity,” nothing that happens to the somatic or body cells can be transmitted to the progeny.

Darwin had put forward a theory of heredity which he called “Pangenesis,” which made out a good case for the admission of the Lamarckian factor. According to this theory all the somatic or body cells give forth still smaller cells which he calls “gemmules.” These gemmules are collected, by some process not explained, in the reproductive organs. Here they are in packets, and these “packets of gemmules” are “the carriers of heredity.” One can easily see how by this process the effects of use and disuse would be transmissible for an organ shrunk by disuse would not be capably represented by an efficient delegation of gemmules at the reproductive headquarters.

Speaking of this theory, Grant Allen in his biography of Darwin says, “Let not the love of the biographer deceive us. Not to mince matters, it was his one conspicuous failure, and is now pretty universally admitted as such.” It must be remembered however, that Darwin was fully aware of its purely speculative character and with his usual caution entitled it the “Provisional Hypothesis of Pangenesis.”

Romanes, one of Weismann’s ablest critics, compares Weismann’s theory with Darwin’s, and while he refuses to defend Pangenesis against Weismann’s charge that it is a wholly unsupported speculation, he replies by contending that the germ-plasm theory lives in precisely the same kind of a glass house.

However that may be, it is quite clear that the germ-plasm theory completely shuts out the Lamarckian factor of evolution in all cases where propagation is sexual.

“But,” say the Neo-Lamarckians, “Darwinism in itself, merely assumes variations without attempting to explain their origin. Natural selection only explains the survival of the fittest; it tells us nothing of what Prof. Cope calls the ‘Origin of the Fittest.’ There must be variation before selection, whence then, comes this variation?” To this question Weismann has a ready reply. “Variation is due to the blending of two wholly different kinds of germ-plasm at conception, producing at birth a result that is not, and cannot be, wholly like the contributor of either.”

And now, at last, the great German is in a corner. If all variations are due to congenital characters only, and these, of course, are only possible because of the combinations secured by sexual reproduction, how do variations arise among non-sexual organisms where such combinations cannot exist?

This is indeed, a poser. But any rejoicing by Weismann’s opponents is quite premature. The sagacity which set those opponents by the ears is still available. There is no attempt to untie that knot; Weismann cuts it with a knife. He empties his antagonist’s sails by a smiling and gracious surrender. Below the sexually reproducing animals, he concedes the operation of the Lamarckian factor. In that unicellular world it is not a special cell that is passed on but the individual itself is continued, and of course any character acquired by the individual will be preserved along with the individual.

Thus then the region of controversy is limited to sexually reproducing organisms and we come to the field where the fiercest fight was made. Do these organisms transmit by heredity those characters or peculiarities acquired by the individual during its own life-time? To this question the Neo-Lamarckians gave a positive affirmative, which Weismann met with an unwavering denial.

Weismann challenged his opponents to produce a single demonstration of such a transmission. Here let us be clear as to what is meant by an acquired character. For illustration, let us suppose a father leaves his son an estate of a thousand acres. That is inheritance. If the son leaves his son the same one thousand acres, that is still inheritance. But if that son increases the estate, during his life-time to two thousand, the second thousand is an “acquired character” of a property nature. There the analogy ceases for there is no dispute as to his ability to transmit both thousands to his heirs by inheritance.

But with “acquired characters” of a biological nature, Weismann maintains this to be impossible. Many specific instances were put forward in refutation of this contention. Herbert Spencer cited the case of the supposed degeneration of the little toe in civilized man as a result of the shoe wearing habit. This it was urged could only have occurred through the transmission of acquired characters and not by natural selection as this diminished toe could not be of any value in the struggle for existence.

But it was shown by measuring the feet of savages, who do not wear shoes, and whose ancestors never wore them, that the small toes of savages had degenerated quite as much.

Then Cesare Lombroso entered the arena leading a camel. According to the Italian criminologist, the camel’s hump had been first acquired by bearing loads and then transmitted by heredity. From the fact that the camel and the llama, which is smooth backed, have something in common, he concludes that camels are really llamas that have recently acquired a hump in the performance of their labors. Lombroso also supported his hump theory by some statements about Hottentot women having developed callouses on their hips by carrying their children on their backs. Unfortunately all Lombroso’s ingenuity was wasted for we happen to possess the geological record of the camel in good condition, and from this history we know that the “ship of the desert” had his hump before the human race appeared when according to Lombroso he should have been a smooth-backed llama. Disappointed as Weismann’s critics were it was hardly feasible to argue that the camel had gotten his hump in those early times by placing loads on his own back.

It was clearly seen that if a case of the transmission of a mutilation could be established, Weismann’s theory would be thereby demolished. A remarkable attempt was made in this direction in 1887 at the meeting of the Association of the German Naturalists at Wiesbaden. To that dignified gathering came Dr. Zacharias with a number of tailless cats. It was asserted that these cats had no tails because their mother had lost her tail through having it run over by a cart wheel. The examination of these specimens proved an entertaining diversion from the regular proceedings, and Prof. Eimer took them seriously enough to refer to them in a later work as “a valuable instance of the transmission of mutilations.”

Weismann, however, refused to be put down. He insisted that in the absence of absolute certainty as to the cart wheel incident, they did not fulfill the first condition of scientific evidence, and Dr. Zacharias wisely admitted later, that this point was well taken. Prof. Poulton had described certain cats with extra toes which he had kept under surveillance for seven generations. “It would be equally justifiable,” says Weismann, “to derive cats with extra toes from an ancestor whose toes had been trodden on, as to derive the tailless cats of the Isle of Man from an ancestor of which the tail had been cut off by a cart passing over it, and thus to regard the existence of the race as a proof of the transmission of mutilations.”

Again Weismann points out that the absence of a tail may not be owing to the mutilation of the mother but to the inherent taillessness of an unknown father. He proceeds to relate how during the year that Dr. Zacharias came with his collection, “My friend, Prof. Schottlius brought me a kitten with an innate rudimentary tail, which he had accidentally discovered as one of a family of kittens at Waldkirch, a small town in the southern part of the Black Forest. A closer investigation resulted in the following rather unexpected discovery. For some time past, tailless kittens have frequently appeared in the families of many different mother cats at Waldkirch, and this fact is explained in the following manner. A clergyman, who lived for some time at Waldkirch had married an English lady who possessed a tailless male Manx cat. The probability that all the tailless cats in Waldkirch are more or less distant descendants of that male cat amounts almost to certainty. Since a male Manx cat has reached the Black Forest, it might equally well arrive at some other place.”

This very same year a popular scientific journal came to the rescue of the transmission theory with the following incident purporting to have taken place 22 years before, in 1864. “A pregnant merino sheep broke its right foreleg about two inches above the knee-joint; the limb was put in splints and healed a long time before the following March, when the animal produced young. The lamb possessed a ring of black wool from two to three inches in breadth round the place at which the mother’s leg had been broken, and upon the same leg.” When this incident was related to Weismann, he replied, “It is a pity that the black wool was not arranged in the form of the inscription ‘to the memory of the fractured leg of my dear mother.’”

Writing in the following year Weismann says, “Furthermore, the mutilations of certain parts of the human body, as practised by different nations from time immemorial, have not in a single instance, led to the malformation or reduction of the parts in question. Such hereditary effects have been produced neither by circumcision nor the removal of the front teeth, nor the boring of holes in the lips or nose, nor the extraordinary artificial crushing and crippling of the feet of Chinese women. No child among any of the nations referred to possesses the slightest trace of these mutilations when born; they have to be acquired anew in each generation.”

While it is undoubtedly true that much in Weismann’s position lacks experimental demonstration, it is equally true that when the heat of the discussion somewhat subsided, his theories were well to the fore, and they have since secured a wide acceptance among competent authorities. It is hardly to be expected that his two greatest critics, Spencer and Haeckel, would look with much favor on a theory the acceptance of which would make necessary the re-writing of those many volumes which constitute their lifework. Lankester, himself no mean authority, in translating Haeckel’s “History of Creation,” feels constrained to say in the preface, “I feel it due to myself to state that I do not agree with him as to a very large part of his views on classification, and as to his belief in the necessity of assuming the ‘transmissibility of acquired characters.’ Readers who have gained an interest in these questions from the brief statements of the present work must, without assuming that Professor Haeckel’s judgment is final, go on to study for themselves the works of Weismann and others which are mentioned with perfect fairness in these pages.”

And Joseph McCabe, the translator of his “Riddle of the Universe,” and “Last Words on Evolution,” has this to say in his introduction to the latter, written two years ago, “To closer students, who are at times impatient of the Lamarckian phraseology of Haeckel—to all, in fact, who would like to see how the same evolutionary truths are expressed without reliance on the inheritance of acquired characters,—I may take the opportunity to say that I have translated for the same publishers, Professor Guenther’s “Darwinism and the Problems of Life,” which will shortly be in their hands.”

It must be admitted that the older view is much less favorable to the Socialist position in sociology than the later theory of Weismann. It is a matter of some satisfaction that so great a critic as Romanes concedes the feasibility of Weismann’s theory while rejecting some of the conclusions which he draws from it. “If Weismann’s theory is true,” says Prof. David Starr-Jordan, “the whole literature of sociology will have to be rewritten!” And another writer insisted that Weismann had reopened the case for Socialism.

If it were true that the terrible results of the degrading conditions forced upon the dwellers in the slums were transmitted to their children by heredity, until in a few generations they became fixed characters, the hopes of Socialists for a regenerated society would be much more difficult to realize. In that case these unfortunate creatures would continue to act in the same discouraging way for several generations, no matter how their environment had been transformed by the corporate action of society. This much at any rate, Weismann has done for us, he has scientifically destroyed that lie.

In this respect, independent sociological experiments and investigations have arrived at the same conclusions as Weismann. Prof. John R. Commons by careful study, reached the following conclusions: That 1.75 per cent of the population of the United States are congenital defectives; that 3.25 per cent are induced defectives, that is, they have not inherited their deficiency; that 2 per cent are possessed of genius and will make their way under the hardest conditions; that 2 per cent are below the Aryan brain level; and that the remaining 91 per cent are normal persons who are neither good nor bad, brilliant nor stupid, criminal nor virtuous, and whose future is entirely decided by the environment which surrounds them during the first fifteen years of their life.

Herman Whittaker, a magazine contributor, states that during eight years in Canada 2,000 boys taken from the London slums by Dr. Barnado passed under his observation on a farm colony. And although most of them had served terms in jail, not more than one per cent reverted to their own former habits, or the habits of their parents.

When it is charged that a transformed social environment will not solve the problem presented by the slum, the sweatshop and the jail, as Socialists assert, we are justified in nailing the statement as false, and a libel on human nature. And in so doing, we are not sentimental dreamers of dreams, crying for the moon, but rigid analysts and investigators, and, as Lassalle once proudly said, “We have behind us the science and the learning of our day.”