Eisen, The Chromoplasts and the Chromioles. 131 



Richard Her twig's paper: ,,Ueber die Bedeutung der Nucleolen" 

 (Separatabdr. aus den >Sitzungsber. der Gesellschaft fiir Morphologic 

 uud Physiologic in Miiueheu, 1898, Heft 1). The conclusions arrived 

 at by the author interest me the more because they are in some points 

 almost identical with those of my own, the latter being the results of 

 a study of the sperinatogenesis of Batrachoseps attenuatus, a batrachian 

 common in California. A preliminary account of these investigations 

 will appear this winter in the ,,Biological Bulletin", the forthcoming- 

 new organ of the Biological Station at Woods Holl. 



The very earliest large cells in the testes are the polymorphous 

 gpermatogonia. They are not only the largest cells in the testes but 

 are also the most interesting. The nucleus of this cell is polymorphous 

 as regards form; that is, the unclear wall is deeply folded without any 

 apparent irregularity. In this stage of the cell we can not speak of 

 chromosomes as they do not exist in any form, shape, or manner. 

 What we see is a. large number of minute granules of even size and 

 shape, and ail capable of being stained intensely by the iron-haemato- 

 xylin method. By a proper afterstaiuing with cougo-red, we find that 

 there are other granules, small and large, and which are of a distinctly 

 different nature from the dark-staining ones. By this method we also 

 demonstrate without any difficulty the two kinds of nucleoli, as well 

 as the various structures of the cytoplasm. The first -mentioned gra- 

 nules are the chrornatin elements which in time will form the chromo- 

 somes. For these granules, which are of constant size, form and 

 number, I have proposed the name chromioles. In the polymor- 

 phous sperinatogouiuin these chromioles are scattered along the nuclear 

 membrane and are connected with each other by threads of liuin, like 

 strings of pearls. The chromioles are perfectly round, and uniform 

 in size. In the earliest stage of the sperinatogouium they lie isolated 

 from each other, later on, under certain conditions, they are grouped 

 in threes If we now turn to the other elements in the nucleus we 

 find them to be as follows: 



The liiiin granules already referred to, which* vary in size only 

 apparently, some being placed or distributed singly while others are 

 bunched together. Their function is to connect the chromioles with 

 each other, as well as to connect and support the chromosomes after 

 the latter are formed. 



With the method employed as stated above, the chromioles stain 

 black or grey, while the liniu granules stain brick red. The larger 

 elements in the nucleus belong to two distinct structures known as 

 nucleoli, true nucleoli and net-knots. 



For reasons that will appear later on, and also for the sake of 

 clearness, I have proposed to call the net-knot chronioplast, while 

 for the true nucleolus I suggested the name of lininoplast. 



9* 



