ON THE STRUCTURE OF CELLS 137 



made many beautiful experiments on the importance 

 of the nucleus, and still more of the centrosome or 

 centrosphere. Thus in one instance he fertilised the 

 non-nucleated portion of the ova of echinoderms of 

 one species by the spermatozoids of another, and 

 found that larvae resulted which resembled the male 

 parent in all cases ; whilst, when the nucleated 

 portion of the egg was fertilised the larvae had 

 intermediate characters betweehrthe two parents. 

 The process of mytosis, as the multiplication of the 

 chromosome is called, is thus of especial importance 

 in the morphology of the cell, and we hope to enter 

 further into the subject in the sequel. There is 

 another aspect of the question, of not less, but 

 probably of even greater moment, and that is the 

 physiological one. It is frequently complained that 

 too much stress is laid upon the morphology of cells, 

 and that the metabolism which occurs in them has 

 not received the same degree of attention. Max Ver- 

 worn lays particular stress upon this point. To him it 

 appears that all the vital phenomena of an organism 

 are only different expressions of its metabolism, and 

 that all the form changes which it undergoes as a 

 part and characteristic of its vital process are merely 

 the outcome of its own characteristic metabolism. 

 " The remarkable fact," as he says, " that this evident 

 truth has been so little taken into consideration, can 

 only be accounted for by the difficulty of combining 

 the two groups of phenomena — metabolism and 

 organic formation." He goes on to add, however, that 

 " metabolism is practically inconceivable without a 



