PHYSIOLOGICAL RELATIONS OF NUCLEUS AND CYTOPLASM 25 1 



manifested by co-ordinated forms of protoplasmic contractility, may 

 go on for some time undisturbed in a mass of cytoplasm deprived of 

 a nucleus. On the other hand, the formation of new chemical or 

 morphological products by the cytoplasm only takes place in the pres- 

 ence of a nucleus. These facts form a complete demonstration that 

 the nucleus plays an essential part not only in the operations of syn- 

 thetic metabolism or chemical synthesis, but also in the morphological 



n>s 



W^iM^ 



r^>^ 









n 







Fig. 113. — Nucleated and non-nuoleated fragments of Amxba. [HOP'ER.] 

 A. D. An Ammha divided into nucleated and non-nucleated halves, five minutes after the opera- 

 tion. C. D. The two halves after eight days, each containing a contractile vacuole. 



dctcr»iination of these operations, i.e. the morphological synthesis of 

 Bernard — a point of capital importance for the theory of inheritance, 

 as will appear beyond. 



Convincing experiments of the same character and leading to the 



same result have been made on the unicellular plants. Klebs 



observed as long ago as 1879 that naked protoplasmic fragments of 



Vanchcria and other algae were incapable of forming a new cellulose 



membrane if devoid of a nucleus ; and he afterwards showed ('87) 



