286 



SCIENCE. 



[N. S. Vol. XXI. No. 530. 



the undivided egg maj' be cut to pieces in 

 any planes taken at random; yet every 

 piece, if of sufficient size, may upon fertil- 

 ization develop as if it were a whole egg 



velopment, if we hold such a theory? 

 Neither the cells nor the regions of the egg 

 seem to have any predestination such as is 

 shown in the molluscan egg. It is the es- 



FiG. 2. — ^Diagram of protoplasmic zones and their distribution at the first cleavage in dif- 

 ferent forms. A, immature egg, assumed to have no definite segregation of protoplasmic 

 stuffs. B, matui-e egg, with protoplasmic zones of horizontal stratification. C, first cleavage, 

 division of the chromosomes. D, E, F, difi'erent types of two-cell stage. D, Dentalium type, 

 the lower zone isolated in one cell. E, Amphioxus, nemertine, or echinoderm type; equal 

 division of the zones. F, hypothetical type with complete separation of two zones at the first 

 cleavage. 



and produce a perfect dwarf. Here is an 

 astounding contrast to the results of our 

 first experiment. What becomes of our 

 theories of prelocalization here, and what 

 becomes of our mechanical theory of de- 



sence of a machine or automaton that its 

 operation is due to its structural configura- 

 tion. Impair or destroy that configuration 

 and the action ceases. But from these eggs 

 we may take away any of the parts, or the 



