400 S. SAGUCHI 



is not, therefore, the production of two cells from one, but the 

 formation of a new cell from an old one, which process he has 

 designated 'renewal of the cells.' Such a mode of cell genesis 

 can no longer be assumed in the present state of our knowledge 

 regarding cell multiplication, just as it is little probable that 

 the 'nebenkerne,' are passed out nucleoli. A comparison of his 

 figures with those of my own shows that his 'nebenkerne' are 

 nothing other than the products of degeneration and that what 

 he mentions as stages of renewal of the cell is but a reversal of 

 the process of degeneration. 



6. THE SO-CALLED 'NEBENKERNE' 



Historical 



a. Shape. Nussbaum ('81, '82) and Gaule ('81), nearly 

 about the same time, but independently of each other, have 

 found certain structures in the pancreatic and other kinds of 

 secretory cells, and have given the name 'nebenkerne' to them. 

 According to the former author, the structures are either solitary 

 or multiple, solid oval or spirally coiled, even curly twisted. 

 A few days after feeding they are found in every cell, while 

 they are rarely met with in the fasting condition. Their biolog- 

 ical significance remained unsolved, although the author brought 

 them into the same category as the 'yolk-nucleus' of the egg- 

 cell found by Wittich, as the 'nebenkern' of the spermatocyte 

 discovered by La Valette St. George, and finally as the struc- 

 tures noticed by Leydig in the epidermal cells of Pelobates 

 larvae. The same or similar structures have since often attracted 

 attention of those investigators who have made a study of the 

 pancreas of the higher and lower vertebrates. And a review of 

 the literature shows that what is described and figured under 

 the name of 'nebenkern,' 'paranucleus,' etc., is not necessarily 

 concerned with one and the same structure, but can be classed 

 into at least two types, as already done by Eberth and Miiller 

 ('92). 



The first type includes those corpuscles which are irregular 

 in shape, and have generally a fibrillar structure. They are 



