330 PROCEEDINGS OF THE ACADEMY OF P^ay, 



cells show a more advanced stage of absorption. Here also the 

 amount of food found at any given time in any particular cell is 

 dependent on the accidents of position, of form and of digestive 

 action iu the lumen. 



The relation of the fat globules to the cytoplasmic structure is 

 again interalveolar (figs. 18 and 19, A). In both these figures 



T 



:.--.J^l 



Fig. 18. — Section of cell X 600 from median portion, "mid-gut" of 

 Porcellio scaber, fed with butter ; intestine fixed after 50 hrs. in Her- 

 mann's Huid by injection from the posterior end. Nucleus is imper- 

 fectly fixed, and cytoplasm is slightly diagrammatic. Fat globules 

 seldom inside alveoles. Pal., palisade ; intima torn ott". 



fat globules appear to have penetrated the nucleus. This appear- 

 ance is due in the former to imperfect fixation, the chromatin not 

 being all precipitated (see section on structure of the nucleus) ; in 

 the latter the globules are in reality above, i. e., at a higher focus 

 than the nucleus. No fat granules are ever found in the nucleus. 



This last statement may fairly raise the question of the identifica- 

 tion of fat globules. In sections from intestines treated with osmic 

 acid and stained in iron-hsematoxylin (fig. 18) how, it may be 

 asked, are blackened fat globules to be distinguished from stained 

 chromatin granules ? Or, more broadly considered, can the fat be 

 distinguished at all by color reactions ? This question is important 



