MORPHOLOGICAL UXTTT OF LIVING BEDCGS. 165 



thread, and die filaments diemselves (mitome) show 

 very duck chromatic granulations, or midosomes, 

 connected by die linin. 



At die moment of reproduction of die cell these 

 granulations blend into a stainable Jiearti which 

 surrounds die filaments, and die latter dispose diem- 

 selves so as to form a single thread. This chromatic 

 filament, which has now become a single thread, is 

 shortened as it thickens spircmf\ / it is then cut into 

 segments, twelve or twenty-four in die case of animak 

 and a larger number in die case of plants. These 

 are chromosomes, or xmdeaar sfgmaUs, or chromatic 

 loops. Their part is a very important one. They 

 are constant in number and permanent during die 

 whole of die life of die cell Let us add tiiat die 

 nucleus still contains accessory elements (nndeoli}, 



The Role of the Nmdems. Experiment has shown 

 tiiat die nucleus presides over die nutrition, die 

 growtix, and die conservation of die celL If, following 

 die example of Balbiani Gruber, Xussbaum, and 

 W. Ronx of Leipzig, we cut into two a cell without 

 injuring die nucleus, die fragment which is denuded 

 of die nucleus continues to perform its functions for 

 some time in die ordinary manner, and in some 

 **ramn* in virtue of its former impulse. It then 

 declines and dies. On die contrary, die fragment 

 provided with die nucleus repairs its 'wound, is 

 reconstituted and continues to live. Thus die nucleus 

 takes a very remarkable part in the reproduction of 

 die cell, but it is still a matter of uncertainty whether 

 its role is here subordinated to tiiat of die cellular 

 body, or if it is pre-eminent. However that may be, 

 it follows from diis experiment tiiat die nucleus 

 presents all the characteristics of a vigorous vitality, 



