CYTOPLASMIC STRUCTURES IN THE SEMINAL EPITHELIUM OF THE OPOSSUM. 75 



in size until it finally comes in contact with the nuclear membrane. In the mean- 

 time the reticular structure is gradually collected on one side of the vacuole (fig. 

 32), and finally detaches itself from the latter, to pass into the protoplasmic lobe. 

 There it appears as a granular body up to the stage represented in figure 33, which 

 corresponds approximately to figure 10, drawn from Benda's preparations. A 

 similar arrangement, although in a somewhat younger stage, is represented by 

 Perroncito for the cat in his figure 89. Later, the apparatus breaks into several 

 smaller bodies of the same structure. Finally, only small granules are found which 

 are eliminated with the protoplasm. Thus it appears that the apparatus does not 

 take any part in the constitution of the ripe spermatozoon, in contradistinction to 

 Perroncito's and Weigl's suggestion reported above, and that similar structures 

 found in the embryonic cells either are derived from the egg's apparatus or are 

 formed de now. 



If we compare the silver preparations with those made from material fixed with 

 Flemming's, Hermann's, or Benda's fluid, we find that in the resting cells (cf . figs. 

 5 and 28) the images are similar. The apparatus is nothing but the outer, darker- 

 staining shell of the idiozome Stockard and Papanicolaou's idioectosome. The 

 points that stand out most clearly in silver preparations are: (1) the behavior of the 

 apparatus during mitosis; (2) that it is identical with the so-called "Idiozomrest." 



Finally, I wish to point out the complete similarity between my conclusions 

 and those of Sjovall, arrived at by entirely different methods; and to add that a 

 study of the testicle of the guinea-pig by means of Ramon y Cajal's method has 

 given me identical results. 



DISCUSSION OF APPARATUS OF GOLGI. 



In my review on the apparatus of Golgi (1914) I endeavored to clear up the 

 question of relationship between this element and other constituents of the proto- 

 plasm. It would perhaps be of interest to reexamine these conclusions in the light 

 of my present and other recent observations. 



A point that I especially desired to settle, as far as possible, was that of the 

 relationship between the apparatus and Holmgren's trophospongium. I came to 

 the conclusion (pages 60-61) that two categories of cells should be distinguished: 

 The neurones and the non-nervous cells with a localized trophospongium on the 

 one side, and the non-nervous cells with a diffuse trophospongium on the other. 

 As to the latter, the identity of both formations can be rejected without further 

 discussion; for, while the trophospongium extends all over the cytoplasm, the 

 apparatus of Golgi is localized at one pole of the nucleus. 1 As to the former, both 

 formations appeared to me to be identical. The difficulty, however, is to reconcile 

 Holmgren's opinion (according to which the trophospongium is in communication 

 with the outside) with that of a large number of authors who hold that the appara- 

 tus of Golgi is limited to the cell. I expressed the view that Holmgren must have 

 confused the apparatus with the exogenous processes which are known to pene- 



1 Exception made for the lutein cells. 



