iment which suggests itself, that of isolating the nucleus 

 from a cell and studying the isolated organ, has been un- 

 successful, owing, no doubt, to the very rapid death of 



a 



the nucleus which occurs nfter its removal from the cell." 



But the fruitful and suggestive results of studying the 

 chemistry of the isolated orn;an are well Imown. 



Altho the nucleus has, since its discovery by Robert 

 Brown in l8oi, been the subject of much morphological in- 

 vest! ('-ati on, most observatios and experiments of a phys- 

 iological n:iture upon this subject are of a comparatively 

 recent date. The earliest experiments appear to be those 



A 



of K. lirandt (1887) upon the rhizoPod Actinosphaerium 

 Eichhornii. After division of this organism, he observed 

 that the pieces which contained nuclei regenerated to com- 

 plete individuals, while those which lacked a nucleus always 

 died without regent ration. Similar observations were made upon 



It 



plant cells by Schmitz (187P). Upon rupture of the membrabes 

 of cells in the alga Valonia utricularis and Siphonocladus 

 Wrisbergi, the protoplasm rounded up into little globules, 

 some of which contained nuclei and some did not. '.'/hile 



"The author has frequently observed a nucleus, which 



had been isolated fi*om an ameba by destruction of the 

 cytoplasm, undergo a rapid darkening, becoming distinctly 

 more opaque in a 'few seconds. While the significance of 

 thi3 phenomenon in not understood, it may be the result 

 of an oxidative change terminating in the death of the 

 organ. 



(10) 



