ANTS AND SOME OTHER INSECTS. 13 



e. g., in the formation of habits but also in instincts. In their ex- 

 treme forms they resemble two terminal branches of a tree, but 

 they may lead to similar results through so-called convergence of 

 the conditions of life (slavery and cattle-keeping among ants and 

 men). The automatic may be more easily derived from the plastic 

 activities than vice versa. One thing is established, however : since 

 a tolerably complicated plastic activity admits of many possibilities 

 of adaptation in the individual brain, it requires much more nerv- 

 ous substance, many more neurons, but has more resistances to 

 overcome in order to attain a complicated result. The activities 

 of an Amoeba belong therefore rather to the plasticity of living 

 molecules, but not as yet to that of cooperating nerve-elements ; as 

 cell-plasticity it should really be designated as "undifferentiated." 1 

 There are formed in certain animals specially complex automatisms, 

 or instincts, which require relatively little plasticity and few neu- 

 rons. In others, on the contrary, there remains relatively consider- 

 able nerve-substance for individual plasticity, while the instincts 

 are less complicated. Other animals, again, have little besides the 

 lower reflex centers and are extremely poor in both kinds of com- 

 plex activities. Still others, finally, are rich in both. Strong so- 

 called "hereditary predispositions" or unfinished instincts consti- 

 tute the phylogenetic transitions between both kinds of activity 

 and are of extraordinarily high development in man. 



Spoken and especially written language, moreover, enable man 

 to exploit his brain to a wonderful extent. This leads us to under- 

 estimate animals. Both in animals and man the true value of the 

 brain is falsified by training, i. e., artificially heightened. We 

 overestimate the powers of the educated negro and the trained dog 

 and underestimate the powers of the illiterate individual and the 

 wild animal. 



I beg your indulgence for this lengthy introduction to my sub- 



1 If I expressly refrain from accepting the premature and unjustifiable identifi- 

 cation of cell-life with a "machine," I nevertheless do not share the so-called vital- 

 istic views. It is quite possible that science may sometime be able to produce liv- 

 ing protoplasm from inorganic matter. The vital forces have undoubtedly origi- 

 nated from physico-chemical forces. But the ultimate nature of the latter and of 

 the assumed material atoms is, of course, metaphysical, i. e., unknowable. 



