186 JOHN SUNDWALL 



dark ring-like contours. This phenomenon is undoubtedly due 

 to variations in the refraction of light as it passes through the 

 granules and does not represent any peculiar constituent of the 

 granules as held by Fleischer. 



The granules in the intercalary duct show the same char- 

 acteristics as do those of the tubules so far as size and the powers 

 of refraction are concerned. 



B. In the second group or type of fresh glands examined, 

 one sees considerable variation in the form and size of the cells 

 of the tubules as well as in the quantity of granules — large bulg- 

 ing cells described under A and smaller cells which have various 

 forms (irregularly cylindrical, pyramidal, or appearing as demi- 

 lunes wedged in between the bulging cells). These smaller 

 cells may be filled with granules or may possess but few. Their 

 nuclei are always round or oval and are separated from the base 

 of the cell by a narrow zone of cytoplasm. 



C. Glands are occasionally seen in which the tubules for the 

 most part are made up of cells which are regular in form — low 

 cylindrical, pyramidal or cuboidal in outline. The granules 

 are confined to the proximal half of the cells. The nuclei are 

 round and oval and do not touch the bases. The lumina of the 

 tubules are wide and open. This condition represents a stage 

 of partial exhaustion of granules. 



At the margin of these fresh tissue preparations, cells are seen 

 which have been ruptured by teasing, cutting, etc. Here the 

 granules are seen passing from these cells into the serum and 

 still retaining the same continuity as they possessed within the 

 cell. In fact the entire margin of the tissue is characterized by 

 the presence of these free granules. In order to exclude the 

 possibility of the more finely formed elements in the blood being 

 responsible for this loose granular mass the serum was carefully 

 filtered before using as a mounting medium. Microscopic 

 examination of the serum, after filtering, revealed no such formed 

 elements. 



When sections of fresh tissue are mounted in physiological 

 salt solution, the cells show the same characteristics as those 

 described for the serum mounted tissue. The loose granules 



