204 JOHN SUNDWALL 



frequently observed these fuchsinophil secretion? granules in 

 the orbital glands of frogs. Just what the significance of these 

 granules is, I am unable to state. The explanation that they 

 represent an intermediate stage between the secretion granules 

 and mitochondria is unwarranted in view of the fact that so few 

 are seen. 



In some cells, though rarely, fvichsinophil globules are seen 

 which are much larger than the secretion granules. It will be 

 well to add here that red blood cells possess a marked affinity for 

 fuchsin, although I was unable to make out mitochondria within 

 them, confirming Cowdry ('14 c). 



Other structures are seen in the cell. These are stained black 

 with the osmic acid. The larger spherical ones undoubtedly 

 are neutral fats. These can be demonstrated with Herxheimer's 

 stain. The finer structures are liposomes. (See discussion 

 under Fat.) 



Dark cells: These cells are so termed because the darkly 

 stained cytoplasm shows no network with empty meshes but 

 instead is either filled wdth deep green stained secretion granules 

 or is continuous. These cells correspond to types 2 and 3 here- 

 tofore described. In form they are irregularly cylindrical, 

 pyramidal, elongated, or hourglass shaped due to indentation 

 caused by the bulging type 1 cells. Many appear as demilunes. 

 The position and form of the nucleus are similar here to that 

 already desci'ibed for these cells. The transitional cells of Noll 

 are seen also wherein the central half of the cell possesses the 

 characteristics of the light cells while the basal half shows the 

 structures described in the dark cells. Throughout the cytoplasm 

 mitochondria are readily observed. In the cells filled with 

 secretion granules they are very plainly seen between the gran- 

 ules. The contrast is marked. In those cells which possess few 

 or no granules, the fed stained mitochondria are readily observed 

 in the dark stained cytopla-m. 



There is no regularity of distribution of mitochondria in the 

 cells of the tubules in any of the types. Frequently one sees 

 them in clumps at the central end, frequently at the basal end. 



