360 KANSAS UNIVERSITY SCIENCE BULLETIN. 



diffusion stages the plasmasome increases in size and the dis- 

 tinction between it and the accessory becomes very marked. 

 In these stages the accessory remains closely appressed to the 

 nuclear wall while the plasmasome is located internally. See 

 figures 3, 5 and 6, plate LXVI. This period during the dif- 

 fusion of chromatin and the growth of the plasmasome can 

 not be considered as belonging to the prophase of the first sper- 

 matocyte. The nucleus increases steadily in size, reaching its 

 maximum when diffusion is complete, so we may consistently 

 call this interval after synizesis the growth period. Its cul- 

 mination marks the installation of important changes, one of 

 which, the re-formation of the chromosomes, has already been 

 described. The accessory meanwhile maintains its former 

 position, size and staining qualities. During the prophase the 

 plasmasome gradually diminishes in size, and finally disappears 

 just before the metaphase. During this time, too, it does not 

 stain so readily with chromatin stains. In the Heidenhain's 

 iron-hsematoxylin preparations the staining quality of the 

 plasmasome varied with the amount of extraction in the iron- 

 alum solution. Occasionally the plasmasome presents a vacuo- 

 lated appearance. This may occur at any time during its 

 history but is more characteristic of the beginning of its dis- 

 solution. Occasionally in the prophase there occur two small 

 homogeneous bodies staining like the plasmasome. As the 

 typical plasmasome is absent and the accessory present these 

 are considered as fragments of the plasmasome. There is no 

 regularity in their occurrence. The cysts in this condition are 

 not frequent and the majority of their cells contain typical 

 plasmasomes. 



In later stages the plasmasome is identified by its shape, be- 

 coming spherical as it decreases in size. Figure 7, plate LXVI, 

 shows a nucleus containing the plasmasome and the accessory. 

 The difference in staining qualities is apparent. The accessory 

 remains in its former position, its form to the observer depend- 

 ing on his point of view. Plate LXVII consists of a series of 

 drawings showing the size relations of the accessory and the 

 plasmasome at the time of synizesis, the growth period and the 

 succeeding prophases. • The drawing of nuclei at the top of the 

 page show the condition of the active chromatin. They are 

 numbered in the order of the changes which they present. 

 For instance, figure 1 shows a nucleus during synizesis. The 

 perpendicular column below figure 1, designated la, shows a 



