The History of Biological Theories

In Germany 31-8 per cent, were of the blonde type, 14-05 per cent, brunette, while the remainder of the population belonged to a mixed type. The fact that blondes were more numerous in Germany led Virchow to suggest that in the south there had been much admixture of the fair-haired Germanic type with the more southerly darker-haired races with Italians, Slovenes, Wallachians, and Bohemians. Virchow also compared skulls, and came to the follow- ing conclusions :

The Celts were dark and round-headed, the Germans and Slavs fair and long-headed. As we pass from North to South, across the Alps, the long-headed types become rarer, the round-heads more numerous. There has, how- ever, been a great deal of crossing between the two types. Most students of these racial problems have put forward similar theories, upon facts supplied by anthropologists. There has been a general tendency to devote a great deal of attention to the details of structure and to neglect psychological elements. The idea that races are held together by their history, religion, political views, and geographical conditions, &c., was gradually dropped ; these theorists thought that race, i. e. physical characters, formed the real link.

Woltmann belonged to this school. He adopted Haeckel's view that the history of man is merely a fragment of the history of the organic world. He condemned the method of writing history which is chiefly concerned with the evolution of political institutions and ideas; and he advocated instead one which would give us some picture of the evolution of the various human races. According to him, all wars, as well as all idealistic movements, are the result of physiological peculiarities. Their ultimate explanation is to be sought in the differences between the various races. Human races are as subject to natural laws as other living organisms; such laws are those of inheritance, of variation, of adaptation, of natural selection, of hybridi- zation, of progress, and of decay.

Among these racial theorists were two schools : The one believed that human characteristics are ex- tremely constant, and that the most potent factor leading to variety has been interbreeding between different races. The consequences of evolution and of the struggle for existence received less attention from this school. The other believed that human characteristics are less con- stant. These were more in sympathy with the Darwinian view, and they attached great importance to the struggle for existence among mankind.

Ammon belonged to the first group. 1 He compared the bodily measurements of recruits drawn from various parts of Germany, and came to the conclusion that two distinct racial types had arisen as the result of intermarriage a taller and a shorter race. Zograff, on the other hand, asserted that the Russian soldier is obviously the result of a cross between three types. Some members of this school have carried this idea of mixed races very far De Lapouge, for example, who asserts that the town- dweller, like a mongrel dog, owes his existence to a mixture of many pure strains. 2 Members of both schools have developed these views until they reached the bizarre. We need only refer to the discovery of Lapouge that ^Nearly all great men have belonged to the fair-haired, long- headed race even when this does not seem to have been true of their relatives. I should not be surprised if the

1 O. Ammon, Die Natiirlicbe Auslese beim Menscben, 1903. * G. de Lapouge, *L'h6redit6 dans la science politique,' Revue antbropologie, culture spread by some other races were to be traced one day to the admixture of some fair-haired long-headed elements with their more sluggish blood an admixture veiled by the passage of time. This same fair-haired race probably formed the ruling caste in Egypt, Chaldea, and Assyria ; the fact is almost established for Persia and India, and is possibly true of Old China. Their importance in Graeco-Roman civilization is practically established, while in modern times the influence of the various living races is directly proportional to the number of long-headed blondes in the ruling classes of their population. To this race belong those Gallic and French elements on which the brilliance of France depends ; the same people give life and move- ment to the masses in Germany.'

Anthropological theorizers of this type were very com- mon in Germany. The majority of them used their theories to glorify Teutonism, and so have been called the 'Germanen theoretiker' to these belong Woltmann, Houston Chamberlain, Lapouge, Giinther, and many of the most virulent Antisemites. It is difficult to estimate how much, if any, truth lies hidden in all this. Modern hybridization experiments have, as a matter of fact, shown that apparently unim- portant characters are obstinately retained by the de- scendants of any such cross. Some of the views expressed by this school seem very fantastic. They teach, for example, that in the struggle for existence the Aryans have had the advantage of a well-developed brain from pre-historic times, and that the cephalic index of the earliest inhabitants of Germany is, on the average, six per cent, smaller than that of the modern Germans. They be- lieve that Natural Selection is still at work separating the dark, round-headed, from the fair, long-headed populations. From the quotations given it is easy to see that these workers' idea of race is a somewhat loose one; it often coin- cides with the popular differentiation of men into 'fair', 'dark', and 'Jewish'. At the beginning of the Great War

these theories played their part in the agitation; the com- ing of peace damped the enthusiasm for such ideas, but they are still fairly common in Germany. The question whether the crossing of two races is advantageous or disadvantageous is an old one. Both views find support. Some assert with Quatrefages that mixed races are quite as intelligent as pure ones, and point to the quickness of the Brazilian Creoles; others point to the supposed lower intelligence of these Creoles to prove the opposite view. Agassiz was among the second group. He thought that the unrest characteristic of Central America was the direct result of the mixture of races living there.

There are other theorists who agree with Darwin, and believe that there is great variability in human charac- teristics. Mankind is subject to Natural Selection, and this is the cause of his intellectual and structural progress. Darwin himself approached this point of view very closely when he reviewed modern societies, and discussed the future of mankind. He examined animal communities for suggestions as to the origins of human society. He pointed out that some altruism is shown by animals who live a social life ; that among the savage horde the 'wise man' is revered, and that he dominates the horde. He pointed out that the possession of several Vise men' gave the group a better chance in the struggle for existence ; further that men are spurred on to new efforts by the praise of their contemporaries; thus their mental capacity increases. Even among civilized men he believed that the struggle for existence is still going on. He feared that too great care of the weak might lead to the downfall of the race, though he hoped that this danger would be partly averted, since in a highly organized society the weaklings are less likely to marry and procreate their kind.

Darwin thought that the law should step in to enhance this natural control of the reproduction of weaklings. He pointed out, also, that riches very often lead to dissipation and so to degeneration, and hence that the accumulation of riches tends to undo its own evil effects. Civilization, since it provides mankind with better food, is advantageous to them. When he weighs the advantages of civilization against its disadvantages, he comes to the conclusion that it does make for progress, though rather slowly (Descent of Man).

Francis Galton, a relative of Darwin, turned his atten- tion more definitely to this question of racial improvement. He was firmly convinced of the inheritance of acquired characters, and suggested certain factors that must lead to the progress of humanity. Among these were the exercise of both body and mind, and the conscious suppression of evil tendencies ; the prevention of marriage between those afflicted with mental disease; the increasing tendency to later marriage, which he thought would prevent over- population. This work forms the basis of the modern eugenic movement, which started in America.

Similar observations still occasionally appear. Schall- mayer, the German sociologist, pictures society as a collection of individuals, very unequally endowed, who Struggle' for existence. He believes that Natural Selection is the only force making for progress. Therefore we must support it if we are to produce a humanity sound in mind and body. He enumerates (1903) the tendencies which aid the process of natural selection, and those which hinder it. He demands that less care be given to the weak, for those hygienic measures which save the weaklings, those laws which make it possible for criminals to produce children, weaken society. For this reason we must increase our sense of responsibility towards the coming generation, we must not abolish capital punishment, and we must follow Schopenhauer's advice and castrate habitual criminals.

Nietsche's philosophy, his differentiation between the morality of the leader and of the slave, his idea of a society produced by the 'will to power', his glorification of bodily strength all this was a very great factor in the spread of such ideas. Bunge and his followers have devoted much attention to the question of the healthiness or otherwise of human society. They assert that modern women are becoming less able to suckle their children. A thought on the same lines is Francis Galton's suggestion that the Spanish race has decayed because, during the years of persecution, it killed annually many thousands of its most independent thinkers. Plotz, Haycraft, Seeck, Reibmayer, Ribot and others have expressed kindred views.

ERE are things which have no history, at least as JL far as our experience goes, crystals, for example. A crystal of rock-salt is always the same, whenever and wherever it may have arisen. When dissolved it disappears, leaving no trace which can be observed in any later forma- tion; the Silurian rock-salt crystals appear to have been exactly similar to those which arise to-day. Before the days of Darwin many biologists had drawn attention to the analogy between crystals and living organisms. They thought living bodies equally absolute and eternal, embody- ing ideas which have endured unchanged since the world began.

When Cuvier introduced the study of palaeontology, when ideas about progress, borrowed from philosophy and political economy, began to enter biology, this concep- tion of the organism as an embodied idea became very prevalent. The talk was now of the 'History of Creation', of the 'perfecting' of ideas, of the 'progress' of organisms. The living thing was no longer thought of as fixed and changeless, but became one of a stream of organisms, standing in a definite relation to those which had preceded and those which came after it. The idea here is not, however, one of actual material continuity ; the continuity was rather an ideal one, representing the development of a thought, an idea.

We may contrast this with Darwin's conception. He, too, taught us to regard organisms as structures with a history, but as the product, not of an idea, but of a series of events in the real world. This was a great thought. We may study an animal as thoroughly as we please ; we may compare it in the most detailed manner with other forms ; but this will not enable us fully to understand its nature, for it bears within it the traces of its past, traces which can only be revealed by historical study.

One result of Darwin's discovery for it was indeed a discovery, was an attempt at a history of the world of living organisms. We must seek for the germs of the present creation in extinct forms and in long-vanished conditions. We must solve the problem of the origin of the vertebrates, discover the story of their evolution, get to know what forms went before them. For every animal, species, genus, or family we must find what it has inherited from the past, and what it itself has added to the story. We must write a history of the whole material creation, just as we would write the history of mankind.

This dream was not realized. It is true that Darwin opened up a new world to investigators. Columbus re- joiced because he thought, when he discovered America, that he had discovered a new route to worlds already known. So Darwin's followers gloried in having found a new way to explain already known facts. They did not originate any new science, any really historical study of morphology; they simply adopted all the old ideas, and explained them all by 'evolution', 'adaptation', 'inheri- tance', and 'the struggle for existence'.

There is a sense in which this Darwinian morphology is the exact antithesis of history. For the writer of history the date is the fundamental fact about any event. His first task is to place his fact in its proper sequence among historical events. He then tries to estimate its importance and its connexion with other events. If he does not know the time of the occurrence, everything he may say about it is necessarily vague and indeed can have but little value.

In the evolutionary study of morphology this sequence is reversed. The date of any biological event (e.g. the date when men first appeared on the earth), is purely a matter of conjecture. It is the relation of this incident to others, e.g. the similarity between Man and the apes, upon which the whole investigation is based. Huss lived before Luther. The writer of history cannot alter this fact, no matter what his opinion of their relative importance. Whatever may be his view of history whether he thinks there has been progress or degeneration, Huss is and re- mains a predecessor of Luther. There is no such estab- lished succession in the world of biology. It depends entirely upon our point of view whether we regard Amphi- oxus as 'older' or more primitive, or 'younger' and less primitive than let us say a lamprey.

Those who believe that there has here been progress call the lamprey 'younger', those who believe that here there has been retrogression call it 'older 5 , than Amphioxus. Here is another even more striking example. Amphioxus is a fish-like animal which still exists to-day. The Icthyo- saurus is a reptile long extinct. Nevertheless the Dar- winians call Amphioxus the more primitive and Icthyo- saurus the more advanced form. The uncertainty among evolutionists as to which forms are the more and which less primitive, is very great indeed. We do not know with absolute certainty the relative position (in time) of any form not even of man himself.

It is generally supposed that the fishes are the most primitive vertebrates, and that the land-inhabiting verte- brates have come from fish-like ancestors. Dohrn, and, quite recently, Koken have declared, however, that they consider fish to be degenerate forms derived from ancestors who lived on the dry landT It is, then, only in name that Darwinian morphology and embryology can be called historical subjects. They are not studies of the past history of modern forms of life ; their methods are purely comparative there is a search for homologies and analogies, just as there was before Darwin's time. This confusion of the comparative with the historical method began with Haeckel. His work dominated the field of speculation from about 1870 on- wards his theories of phylogeny, his law of biogenesis, his genealogical trees, his rejection of the 'type 3 system.

Haeckel, of course, had aroused considerable opposition, and workers, when they published their discoveries, their confirmations and refutations of the theories that were being discussed, usually preferred to refer to Gegenbaur, to Ray Lankester, to Balfour, Hertwig and other less notorious scientists. These were men who had accepted Haeckel's views and had succeeded in presenting them in a form that made them suitable for teaching purposes but they had not fundamentally altered them.

In the eighteenth century, and even earlier, philosophers often discussed the question of transitional forms. Leib- nitz prophesied that one day an organism would be dis- covered in which the qualities of plants and animals would be found combined. When the fresh water polyp (Hydra) was discovered, Leibnitz's disciple Bonnet declared it one of those intermediate forms ; to-day it is, of course, re- garded as wholly animal. These workers had no idea, however, of historical evolution when they discussed transitional forms. We owe that idea, in its modern sense, to Lamarck and after him to Darwin, who held that since there are no species, genera, or orders in Nature, we must conclude that evolution has proceeded by very gradual steps.

The morphologists set to work to find forms intermediate between genera, and even between larger groups. Every new discovery of any such form was used to support the argument that nature proceeds gradually, and not by leaps. Lamarck had said that the Duckbill (Ornitborbyn- chus)> an animal which had captured the imagination of his contemporaries, was intermediate between a mammal and a bird. The animal is shaped like an otter; like the birds, it has a toothless beak, a cloaca, and lays eggs; yet it is a four-footed, hairy mammal, and the 'young are suckled by their mother.

Lamarck's arguments are not convincing. An inter- mediate form, to bring assurance, should share the char- acters of the two groups which it links up to such an extent that it is impossible to say to which of the groups it belongs. The duckbill does not fulfil this condition. It is unmis- takably a mammal, although, in addition to its mammalian characters, it has a few that are avian and even reptilian. From Lamarck onwards a succession of these inter- mediate types has been constantly discovered. Their fate has always been the same. Discussion has raged round them for a time, but eventually they have been included in one or other of the established groups.

The origin of the vertebrates has been a subject of controversy ever since the formulation of his theory by Darwin. At one time the discussion turned round the Tunicates or seasquirts. These animals have a body sur- rounded by a fleshy cloak or envelope, to which the name Tunicate refers. The mouth is situated at the anterior end of the simple body, and behind the mouth are the gill-slits. The alimentary canal is bent upon itself, so that it opens into a cloaca which lies near the mouth. The nervous system is reduced to a ganglion between these two external apertures, and the heart lies behind the gill-slits. Cuvier and von Baer placed these animals among the invertebrates. Kovalevsky, the Russian naturalist, was the first to suggest that they had vertebrate affinities, but von Baer did not accept this view. He pictured the body of one of these Tunicates placed so that the mouth and cloaca were posterior, the nerve-centre ventral in position. Then the apertures in the Tunicate correspond in position to those openings beneath the shells of shell-fish through which water streams in and out. There is a certain analogy between the structure of the whole body in the two forms. Kovalevsky, on the other hand, compared these forms with Amphioxus, the simplest of all the vertebrates.

This latter is a fish-like animal about five inches long. It has neither bones nor limbs, and its internal structure is extremely simple. It was discovered by Pallas in 1774. He thought it was a shell-less mollusc. That it had certain affinities with the vertebrates was proved by Kovalevsky in 1864. He pointed out that there are many resemblances between the developmental stages of Amphioxus and of the Tunicates. In both the nervous system is dorsal in position and is derived from ectoderm.

The young of the Tunicates are more highly developed than the adults. While adults are sedentary, the larvae are free-swimming and look like miniature tadpoles. In the tail region, ventral to the nervous system, there is a supporting rod similar to the notochord of Amphioxus. It had already been recognized that the notochord repre- sents a vertebral column in its simplest form. This work of Kovalevsky was confirmed and carried further by other investigators. They found many similari- ties between the early stages of both Amphioxus and the Tunicates. Thus:

(a) Both groups possess, when immature, a dorsal nerve tube opening by a neuropore. (c) In both the anterior portion of the alimentary canal bears gill-slits. (d) In both forms there is a tail, posterior to the alimen- tary canal, in which there is a suggestion of metameric segmentation, both of the nervous system and of the muscles. In spite of these similarities all workers do not agree that the ascidian lies between the vertebrates and the invertebrates. Semper suggested that the vertebrates have been evolved from the annelid worms. This theory depended chiefly on a supposed similarity between the excretory organs in the two groups. Hubrecht thought that vertebrate affinities were to be sought for among the Nemertean or Ribbon Worms. Patten would derive verte- brates from a form like the Kingcrab Limulus a crusta- cean ; others again saw the sought-for ancestor in Balano- glossus, and there have been many other suggestions.