PLATE 2 
EXPLANATION OF FIGURES 
9 A pancreatic acinus showing perfectly definite secretory polarity with the 
blackened reticular material placed in each cell between the nucleus and the 
lumen, same method. 
10 Group of parathyroid cells from a piece of tissue centrifuged in the direc- 
tion of the arrow in normal saline for forty-five minutes, at about 4,500 revolu- 
tions per minute, same method. 
11 Parathyroid cells fixed in Bensley’s acetic-osmic-bichromate mixture 
and impregnated with 2 per cent osmic acid according to the method of Kolatchev 
as suggested by Ono. The reticular material is blackened, but is not very defi- 
nitely oriented. 
12 Parathyroid cells prepared by Da Fano’s cobalt nitrate silver method in 
which the blackened reticular material shows but slight evidence of polar 
arrangement. 
13 Cluster of parathyroid cells from the same centrifuged tissue as figure 10, 
showing a grouping of the cells with definite orientation of the reticular material 
between the nucleus and the lumen. 
14 A small group of cells from the anterior lobe of the hypophysis, also 
prepared by Da Fano’s method, and showing how variable is the position of the 
reticular material in the cytoplasm. There appears to be no conformity in its 
location even in adjacent cells. 
36 
