MODERN BIOLOGY 313 



of the body in their search for food on the shores, swimming birds their 

 webbed feet through stretching out their toes during their movements in the 

 water. In connexion herewith he declares that if a number of children were 

 to be deprived at birth of their left eye and they were allowed to have children 

 by one another, there would eventually arise after a few generations a one- 

 eyed race of men. But it is not merely influences of this detailed kind that 

 re create the life-forms; but also the effect of geographical conditions in 

 general; climate, humidity, abundance or scarcity of food, have in the long 

 run had a transforming influence upon animals as a whole and have produced 

 new organs or caused the old ones to disappear. This is rendered possible 

 owing to the fact that there is an infinity of time at the disposal of evolution; 

 "Time has no limits," says Lamarck explicitly. Thus life becomes purely 

 and simply a mechanical process; all its manifestations are motion and noth- 

 ing else. It is true, existence has a Supreme Originator, for whose name 

 Lamarck always si^ows respect, but His greatness lies in the fact that He has 

 created nature in such a way that it has developed its profuse multiplicity 

 without interference from without. This development out of given qualifica- 

 tions Lamarck does not succeed in establishing, however; "nature" appears 

 constantly as a creative power and is spoken of in terms suggestive of a 

 personality; this is especially so in Philosophie ■::oologique, from which a few 

 examples will be cited further on in this chapter. 



His theory of life- fluid 

 In the continuation of Kecherches Lamarck further develops his mechanical 

 theory of life, which to him is really the main problem, in which his evolution 

 theory is only one detail among many. To his mind, life itself is the condition 

 in all the parts of the body that makes their organic movements possible. 

 This condition consists in the existence of " T or gasme vital," a state of tension, 

 a "tonus," which maintains the molecules in the soft parts of the body in a 

 definite position and which by increasing and diminishing enables the organs 

 to contract and expand. The cause of this tension is a fluid that is secreted 

 by the blood and thence absorbed by all the organs of the body, but is particu- 

 larly concentrated in the nervous system. This fluid is really a peculiar variety 

 of fire, related to heat and electricity, a "feu ethere." It is transmitted on 

 fertilization from the male sexual product to the embryo, which derives 

 life from it — immediately in mammals, but not until later in the bird's ^gg, 

 which only receives life by brooding. But this same fluid exists scattered 

 everywhere throughout nature, so that everywhere, and especially in hot 

 countries, with their humid climate, there takes place a spontaneous produc- 

 tion of life. Lamarck asserts that this spontaneous generation under the influ- 

 ence of heat, light, and electricity goes on incessantly, the lowest animal 

 forms — and even plant forms — being continually reproduced out of 

 inanimate matter; he declares it to be probable that the fresh-water polypi 



