208 Page May and Walker 



cell, other cells intermediate in character between these two very different 

 types were found during the present investigations. The nucleoli seemed 

 to be taken into the cytoplasm of the capsular cells, of the intermediate 

 forms, and of the leucocytes indifferently. 



The present observations do not seem in accordance with the interpreta- 

 tion of Flemming or of Oscar and Richard Hertwig, as regards the 

 function of the nucleolus. These observers held that the nucleoli supply 

 nutriment which contributes to the formation of the chromosomes during 

 the process of mitosis, and this interpretation is perhaps strengthened by 

 the fact that the nucleolus, when present, seems then to disintegrate. 

 As, however, the phenomenon of mitosis has not hitherto been observed 

 among the nerve cells of the adult mammal, and apparently does not occur, 

 the function of the nucleoli here dealt with must be something entirely 

 independent of the formation of chromosomes as they appear during 

 mitosis. That the nucleoli are constantly being increased in number, even 

 in adult life, by the process described in this paper, proves that they 

 subserve some important function, but whether this is in the nature of an 

 excretion, secretion or some other form of cell phenomenon, there does not 

 as yet appear to be any direct evidence. 



CONX'LUSIOXS. 



The conclusions arrived at from the observations here described are — 



1. That the nucleoli of the nerve cells described multiply continually, 

 generally by a process of budding, more rarely by an equal division in bulk 

 of a pre-existing nucleolus. 



2. That the nucleoli pass out of the nucleus, and in the process their 

 -staining reaction changes. 



3. After passing out of the nucleus the nucleoli become granular in 

 appearance, and increase in size. The increase in size would appear to be 

 due to the lessened density of the contents, rather than to an increase in 

 substance. 



4. The nucleoli sometimes pass bodily out of the nerve cell (peri-karyon), 

 and are taken into the cytoplasm of leucocytes or capsular cells. At other 

 times the substance of the nucleoli seems to pass in small portions from the 

 cytoplasm of the nerve cell into that of a capsular cell or a leucocyte. 



