176 



JOHN SUNDWALL 



Secretion granules in the cells of the intercalary duct are described 

 by him. The chief characteristics then of the intercalary duct 

 according to these observers are the more intense staining re- 

 action and the presence of granules. 



The deeper staining of these ducts is readily seen in sections 

 of tissue fixed in the ordinary solutions and stained with iron 

 haematoxylin and neutral stains. 



For the study of the intercalary duct I found that the most 

 interesting results were obtained from tissues fixed in Zenker's, 

 embedded in celloidin, and stained in muchaematein. This 

 stain was prepared and used according to Bensley's method 



Fig. 11 Inteifahiiy duct and tubules. Stipple board drawing projection. 

 The granules of the intercalary duct are stained specifically with muchaematein, 

 Tech. IV, 1. ^4., unstained intralobular duct; B, intercalary duct with granules; 

 C, tubules; D, transitional cells. 



(Technique IV, 1.) The sections were cut from 10-20^ thick. 

 It was found that bjr following this technique the granules of 

 the intercalary duct are stained specifically and definitely blue 

 while the remaining tissue is unstained (fig. 11). This 

 method therefore is of great value in the study of the intercalarj^ 

 duct and its relations to the intralobular duct on the one hand 

 and the alveoli or tubules on the other. In the preparation of 

 these sections it was found that after fixation in Zenker's the 

 tissue should be thoroughlj^ washed in order to remove as much 

 of the salts as possible, for if iodine is used for this purpose 

 the distinct granular stain cannot be obtained. Furthermore, 



