Cytological studies on the spinning glands of Platyphylax etc. 417 



8. The even optical structure of the cytoplasm in the cells of 

 most normal glands becomes decidedl}^ changed after activity. We 

 admit that all glands after what we suppose is an equal period of 

 activity, do not show exactly the same structure; we are not, however, 

 sure that a gland which has supposedly been active for a certain 

 period has in reality secreted more than the glands of some other 

 larvae which were supposedly active for a shorter period. In this 

 connection we would call attention to the fact that Hodge [8] has 

 shown that a strong stimulus may in two hours cause a change that 

 it takes a weaker stimulus ten hours to bring about; also to Lang- 

 ley's [13] view that both anabolism and katabolism go on at the 

 same time, the appearance of a cell depending, it may be, upon the 

 one or the other being in the ascendency. The change during the 

 first twenty-four hours of activity in greater than that caused by any 

 other equal period. 



9. The chromatin granules lie imbedded in a linin reticulum. 



10. The activity of the gland causes the membrane on that sur- 

 face of the nucleus which lies nearest the outer margin of the gland 

 to become irregular, the most noticeable feature in the irregularity being 

 the pointed processes extending into the cytoplasm. This nuclear mem- 

 brane may often become indistinct. Secretory activity does not cause 

 the nuclei to become swollen (Heidenhain [5]). 



11. No plasmosoma or other special structure is formed in the 

 nucleus during secretion (Ogata [l'^])- 



12. As a result of activity the „nucléoles" become very irregular 

 in shape. 



Madison, June 1905. 



Zoological Laboratory, University of Wisconsin. 



Internationale Monatsschrift f. Anat. u. Phys. XXllI. 27 



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