262 
George Arnold 
(2) The zyraogen graniiles, which are confined to the inner vacuolated 
zone. They are considerably larger in their mature condition 
than the mitoehondria. 
(3) Very small granules, of a very even size, which are distributed 
all through the cytoplasm, but may be limited occasionally to the 
basal zone. 
The first two are dealt with later on, in the section on the function 
of the chondriosome, the last will be described now. 
The last are well preserved in Zexker’s fixative, Flemhing’s strong 
solution, and Benda’s modification of Flemming’s solution (Figs. 1 and 
13 sm) so that unlike the zymogen granules, or the mitoehondria, osmic 
acid is not a necessity for their successful fixation. They are not so baso- 
phile as those structures, and can be demonstrated by prolonged staining 
even with acid dyes, such as Bordeaux Red, Lichtgrün and Acid Fuchsin. 
On the other hand, in spite of their slight affinity for acid dyes, they 
cannot be seen in material fixed in Altmann’s potassium bichromate- 
osmic acid mixture. The latter, unlike the other fixatives mentioned, 
contains no aeetic acid, and therefore it is very probable that the presence 
of that compound is necessary for their preservation. If this conclusion 
is correct, they are by that quality to be distinguished at once from mito- 
chondria, on which acetic acid, in any but very minute quantities, has 
a destructive action. Another fact in support of that view is, that it is 
not possible to trace any direct connection between them and the chon- 
driokonts or mitoehondria. Moreover, their distribution in the c-ells is 
peculiar, for they do not occur in all the cells, at least not at the same time. 
They are to be seen in not more than two or three cells out of the half 
dozen or more which are visible in the cross-section of any alveolus. 
The question arises whetlicr, they are produced during certain phases 
of the life cycle of all the cells, or whether they are a permanent cell organ 
confined to a particular group of the alveolar cells. 
The latter view is the more probable, since they are still to be seen 
in cells from which all the zymogen granules have been excreted(Fig. 13 sm), 
even in pancreas which has been subjected to the action of pilocarpine. 
Not to be confused with them are some small granules, derived from 
the breaking down of the exereted zymogen granules, to be found in the 
lumen of the alveoli. These, unlike the granules which have just been 
described, are stainable after Altmann’s fixation. 
As remarked above, the small granules, may be distributed evenlv 
through the wliole of the cytoplasm, or confined to the basal zone. The 
