completely explained, we do not possess the right 

 to discard them and resort to the help of this power, 

 which exists only in the imagination. Can we explain 

 the phenomenon of crystallization? Why does sodium 

 chloride always crystallize in the form of a cube, 

 and pure carbon in the form of an octahedron? Is 

 not the formation of globules of division, from the 

 point of view of form, a kind of crystallization of 

 organic matter? The successes of organic chemistry 

 belong to us, because the processes accomplished 

 during nutrition, respiration, and excretion are 

 more satisfactorily explained by means of physics and 

 chemistry than by means of a special vital power. This 

 power has retreated into the dark field of our 

 knowledge about the functions of brain and nerves and 

 still dominates in the sphere of embryology. However, 

 new histological directions make the study of the 

 vital power even more unsteady in this sphere, so we 

 are not far from the time when chemistry will 

 completely exclude it from there as well. The concept 

 of vital power must remain as a reminder of our 

 previous ignorance. Only quite recently the influence 

 of semen on the yolk was called dynamical; this 

 expression shows only that the phenomena of fertiliza- 

 tion could not be explained, (p. 170) 



In these words Warnek exhibited the materialistic world 

 view with complete clarity. He decisively objected against 

 the dull idea of the vital power for the explanation of 

 phenomena of organic life. The only way in which this 

 explanation could be achieved Warnek considered to be the 

 physico-chemical investigations of vital phenomena. Regarding 

 fertilization as a chemical process, Warnek thought that 

 the subsequent transformations of the dividing ovum have as 

 their source continuous chemical changes. Of course, Warnek' s 

 materialism has a mechanical character, but it is not 

 excessively simplified vulgar materialism. 



Warnek 's embryological opinions are expressed in his 

 theses, the most important being: 



The yolk mass after fertilization undergoes chemical 

 changes, therefore the fertilization itself must be regarded 

 as a chemical process. It causes changes in the unfertilized 

 ovum whicli are necessary for further development of the embryo 



557 



