266 
George Arnold 
by Haematoxylin. (This is not shown in the drawings except in Figs. 8 
and 9: in the other figures, some of the chondriokonts are eoloured faintly 
in order to give a three dimensional representation of the picture.) 
Whether the mitoehondria also fragment into smaller granules was 
not aseertainable with certainty ; the presence of small granules in proximity 
to the mitoehondria in cells such as Fig. 6, suggest tliat they do so. 
(2) Phase of exeretion. 
Onee the inner zone becomes full of zymogen granules, the phase of 
exeretion is entered. The granules are slowly extruded into the lumen 
of the alveoli; and the process continues until the chondriokonts are 
exhausted, and until no more granules are given off from them to re- 
plaee tliose whieh have already left the cell. 
The act of exeretion may be foreibly liastened by a drug like Pilo- 
carpine. Thus in guinea-pig No. 4d, after a dose of the drug = 1 / 32 grain, 
many of the cells contain abnormally large vacuoles, whieh were probably 
formed by the violent extrusion simultaneously of a whole group of granules. 
It is at the end of this phase and in the following phase of rest, that 
the chondriokonts re ach their smallest dimensions, (Figs. 8 and 9). They 
are then less than half their maximum size (cf. Figs. 4 and 9), and are for 
the greater part confined to the lower half of the basal zone. 
(3) The resting phase, perhaps might be more correctly called the phase 
of exhaustion. 
Apart from the minimum size of the chondriokonts, it is also c-harac- 
terized by the total absence of zymogen granules in the inner zone (Fig. 9). 
It is important to note that at no matter what stage the cell may be 
examined, it always contains some chondriokonts and mitoehondria. 
This is a natural corollary of the permanence of the chondriosome as 
a cell organ. f ; f i ' ' '* - 
When the inner zone is full of zymogen granules, the vacuolar struc- 
ture of that region is obscured, but in the middle portion where the granules 
are not so plentiful, many gramdes can be seen to lie eacli within a vacuole. 
This is more readily seen in sections of pancreas which have been fixed 
in Flemming’s strong solution and stained with Saffranin-Methylene 
blue-Orange G. 
Whether all the mature zymogen granules are enelosed in fluid- 
containing vacuoles, I have not been able to ascertain, but they have been 
so described by many observers. 
When the granules are being discharged into the lumen of the alveolus, 
the fluid in the vacuoles is undoubtedly also passed out, otherwise it would 
be difficult to account for the great difference in the size of the replete 
