334 'Journal of Cofuparative Neurology and Psychology. 



"anscbaulicli" Ly "searching about for a satisfactory mechanical 

 scheme of structure" (31, p. 188). Such he feels that he finds in 

 all develo]3mental processes, both in development from the egg, and 

 in the development of new features in movement and the organs of 

 movement. ''It is greatly to be regretted that we must give up the 

 hope of finding an anschaulicli structural schema for animal develop- 

 ment. But there is no structure that could explain (veranschau- 

 lichen) its own production" (31, p. 185). Since, then, it is impos- 

 sible to bring development under the <^)nly point of view which seems 

 to V. Uexkiill to give a satisfactory explanation, he finds it necessary 

 to take refuge in vitalism. He is, however, under no illusions as 

 to vitalism's being an explanation ; it is a mere renunciation ; "when 

 we therefore give over the production of form to vitalism, this giv- 

 ing over involves a renunciation of all real understanding in this 

 science" (31, p. 187). In his latest jjajjor v. UexkiUl counts himself, 

 if I understand him correctly, as a vitalist so far as develo})mental 

 processes go, but as a "machinalist" so far as the functioning of 

 developed organs is concerned (33, ]). 1-4). 



If in place of nuiking "Anschaulichkeit" the end to be reached, 

 one takes verifiableness as his aim, a very different set of views 

 will be reached in biology. There are many fields of exact science 

 in which such "Anschaulichkeit" as v. Uexkiill demands is not re- 

 (piii-ed. To understand how water is produced from ojiygen and 

 hydrogen, most chemists do not construct a fictitious machine on the 

 plan of a flour mill or a dynamo. They merely accept the fact as a 

 datum, in connection with other similar facts. V. Uexkiill himself 

 mentions a inimber of fields of science which are not "anschaulicli" 

 in character (33, p. 16), so that it seems extraordinary to found 

 vitalism on the basis that biology is similar to other sciences in this 

 respect ! The only condition that science requires in oi-der that 

 accepted principles of explanation shall apply is this ; that differ- 

 ences in resulting conditions shall always be found to l)e i)re- 

 ceded by differences in foregoing conditions, so that nothing shall 

 happen undetermined. But why oxygen and hydrogen in the pro- 

 portion of one to two should give the properties of water rather 

 than those of alcohol we do not know any more than we know why 



