494 



NATURE 



\Oct. 4, 1877 



theless now generally acknowledj^ed. Only the ignorant to-day 

 smile incredulously at the explanation that the colossal moun- 

 tain chains of the Alps, the snow-covered summits of which we 

 see glistening in the far distance, are nothing else but the 

 hardened deposits of the sea. The structure of these stratified 

 mountains and the nature of the fossils they inclose do not admit 

 of another explanation ; and yet it cannot be proved in an exact 

 way. In the same manner all geologists now unanimously sup- 

 pose a certain systematic succession of the mountain strata, corre- 

 sponding to their different ages ; and yet this system of strata is 

 nowhere perfectly present upon the earth. But our phylogeneiic 

 hypotheses may claim the same value as Is given to these 

 generally recognised geological hyiiotheses. The only difference 

 is that the enormous structure of hypotheses in geology is far 

 more perfect, simple, and easier to understand, than that of 

 youthful phylogeny. 



Thus these historical sciences of nature, geology and phylogeny, 

 now form the uniting bond between the exact natural sciences on 

 the one hand, and the historical sciences of the intelleC, or pure 

 sciences, on the other. The whole of biology, in particular 

 systematic zoology and botany, are thus raised to the rank of a 

 true natural history, an honourable title, which these sciences 

 have borne long ago, but which they only now merit truly. If 

 indeed to-day in many quarters, even in official ones, they are 

 designated as "descriptive natural sciences," and opposed to 

 the "explanatory " ones, this only shows what a false idea had 

 hitherto been entertained of their true object. Since the "natural 

 systeni " of organisms has been recognised as their ancestral 

 pedigree, ilie living phylogeny of classes and species takes the 

 place of dead descriptive syslematics. 



However highly we may estimate this enormous progress of 

 morphology, jet it would not suffice by itself to explain the 

 extraordinary effect of the evolution doctrine of to-day upon 

 science in general. This, as you know, rests upon a single special 

 deduction drawn from the theory of descent, upon its application 

 to man. The very old question of the origin of our own race is 

 by this theory solved for the first time in a natural scientific 

 sense. If the theory of evolution is true at all, if there exists a 

 natural phylogeny at all, then man also, the crown of creation, 

 has resulted from the form vertebrata, from the class mammalia, 

 from the sub-class placciitalia, from the order apes. If Linnaeus, 

 in 1735, in his system of nature, already united man with apes 

 and bats in the ( rder of primates, if all following zoologists could 

 not move him out of the class of mammalia, then this unanimously 

 recognised S)stematic position can, phylogenetically, only be 

 interpreted as descent from that class of animals. 



All attempts to shake this most important deduction from the 

 evolution doctrine are futile ; it is vain to try to keep a 

 particular exceptional position for man, by constructing for him 

 a special line of ancestor?, separated from those of the verte- 

 brata. The phylogeneiic archives of comparative anatomy, 

 ontogeny, and palneontology, speak too distinctly in favour of an 

 identical and uniform (einheillich) descent of all vertebrata from 

 a single common ancestral form, to permit of our having any 

 doubts on this subject now. Not a single investigator and 

 comparer of languages thinks it possible that languages as widely 

 different as the German, Russian, Latin, Greek, and Indian 

 languages h.ave developed from different original languages. On 

 the contrary, all linguists, by critical comparison of the structure 

 and the development of these different langu.ages, airive unani- 

 mously at the conviction that they all have emanated from a 

 single Aryan or Indo-Germanic mother language. Just in the same 

 way all morphologists arrive at the firm conviction th-it all 

 vertebrata, from the amphioxus upwards to man himself, all 

 fishes, amphibia, reptiles, birds, and mammals descend originally 

 from a single vertebrate ancestor ; for we cannot imagine that 

 all the different and highly-complicated conditions of life, which, 

 through a long series of processes or stages of development, led 

 to the typical formation of a vertebrate, have accidentally 

 happened together more than once in the course of the earth's 

 history. 



For our consideration to-day only the general conception 

 of the vertebrate-origin of man is of importance, we will not 

 occupy our time with the single ancestral stages of our pedigree. 

 I would only in passing point out that at least the principal 

 stages of the same are now considered as firmly established, 

 thanks to the excellent labours of our most illustrious morpho- 

 logists, Gegenbaur and Huxley before all others. Of course it 

 is still often supposed that thus, even to-day, only the origin of 

 the human body is explained, but not that of our spiritual 



activity. In the face of this important objection we must 

 remember, before all else, the physiological fact, that our intel- 

 lectual life is inseparably united with the organisation of our 

 central nervous system. The latter, however, is composed 

 exactly like that of all higher vertebrata, and originates in 

 exactly the same way. Also, according to Huxley's investiga- 

 tions, the differences between the structure of the brain of man 

 and that of the higher apes are far less important than the cor- 

 responding differences between the higher and lower apes. Now 

 as the function or work of each organ cannot be imagined with- 

 out the organ itself, and as the function is everywhere deireloped 

 along with the org.an, we are forced to suppose that our psychical 

 activity has ileveloped slowly and gradually in connection with 

 the phylogennic development of our brain. 



For the rest this highly significant "soul question" appears to 

 us in quite a different light to-day from what it did twenty, yes, even 

 ten, years ago. Whatever we may imagine to be the nature of 

 the connection of soul and body, of mind and matter, so much 

 results with perfect clearness from the evolution doctrine of 

 to-day that at least all organic matter — if indeed not all matter — 

 is, in a certain sense, animated. First of all, we have been 

 taught by advanced microscopical investigation, that the ana- 

 tomical elementary parts of organisms, the cells, universally 

 possess individual animated life (allgemein ein inJiviiluelles 

 Seelenlilhn bailzen]. Since .Schleiden founded, forty years ago 

 at Jena, the highly-significant cell theory for the vegetable king- 

 dom, and Schwann soon afterwards applied the same to the 

 animal world, we universally ascribe to these microscopical life- 

 beings an individual and independent life ; they are the true 

 " individuals of the first order," the " elementary organisms " of 

 Biiicke. The grand and highly fertile application which 

 Virchow, in his " Cellular Pathology," made of the cell theory 

 with regard to the entire domain of theoretical medicine, is 

 indeed based upon his considering the cells no longer as the 

 dead passive building stones of the organism, but as the living, 

 active state citizens of the same. 



This conception is finally confirmed by the study of infusoria, 

 amceha^, and other unicellular organisms, because here we find 

 with the single cells, living in isolation, the same manifestation 

 of soul-life, sensation, and conception, volition and motion, as 

 wiih the higher animals, composed of many cells ! Both in the 

 case of these latter social cells, as well as in that of the former 

 hermit-cells, the soul-life of the cell is tied to one and the same 

 most important cell substance— /ri>/n/A7j«. We even see in 

 the monera and other most simple organisms that single detached 

 pieces of protoplasm possess motion and sensation, just like the 

 whole cell. Accordingly, we must suppose that the cell-soul, 

 the foundation of empirical psychology, is a compound itself, 

 namely, the total result of the psychic activities of the 

 protoplasm-molecules, which we shortly call plastidule. The 

 plastiilule-soul would therefore be the last factor of organic 

 soul-life. 



But has the evolution doctrine of the present day thus exhausted 

 its psychological analysis ? Not at all ! On the contrary, we 

 are taught by modern organic chemistry that the peculiar physical 

 and chemical properties of an element, of caibon, in its compli- 

 cated combination with other elements, cause the peculiar physio- 

 logical properties of organic compounds, and before all others, 

 of protoplasm. The monera, consisting exclusively of proto- 

 plasm, here form the bridge over the deep chasm between 

 organic and anorganic nature. They show us how the simplest 

 and oldest organisms must have originally sprung from anorganic 

 carbon compounds. If therefore in spontaneous generation a 

 certain number of carbon atoms unite with a number of atoms of 

 hydrogen, oxygen, nitrogen, and sulphur to form the unity of a 

 plastidule (or molecule of protoplasm), we must regard the plas- 

 tidule-soul, i.e., the total sum of its life-activities, as the necessary 

 product of the forces of these united atoms. The sum of the 

 central atomic forces we may call atom-soul in a consequentially 

 monistic sense. By accidental meeting and varied combination 

 of the constant and unchangeable atom-souls the diverse and 

 highly variable plastidule-souls originate, the molecular factors 

 of organic life. 



Arrived at this most extreme psychological consequence of our 

 monistic doctrine of evolution, we meet with those old concep- 

 tions of the animation of all matter, which already in the philo- 

 sophy of Democritus, Spinoza, Bruno, Leibnitz, and Schopenhauer 

 have found varied expresfion ; because all soul-life can finally 

 be reduced to the two elementary functions of sensation and 

 motion, to their reciprocal action in reflex motion. The simple 



