The röle of the chondriosomes in the cells of the guinea-pig’s pancreas. 265 
(1) Phase of secretion. 
At the very beginning of this phase, the cell is characterized by the 
presence in the basal zone of chondriokonts and mitochondria which have 
reached their largest dimensions (Fig. 5). The inner zone is almost devoid 
of zymogen grannles. The chondriokonts at this stage are very deeply 
stained by the Haematoxylin, and are markedly thicker at the end which 
is directed towards the base of the cell 1 ) (Figs. 4 and 5). 
The longer chondriokonts lie at about the level of the nucleus, and 
generally parallel to the long axis of the cell. Some of the shorter ones 
invade the clear inner vacuolated zone, and exhibit a moniliform appear- 
ance, especially at their proximal extremity (Figs. 4 and 5). 
Similarly, some of the longer chondriokonts also show a beaded struc- 
ture, a condition which becomes more common as the elaboration of the 
zymogen granules proceeds. 
The next Step in the process is that the beading at the proximal 
extremity becomes more and more pronounced, tili eventually a section 
is completely separated off from the rest of the chondriokont. Numerous 
examples at just this stage can be seen in all cells in the secretory phase 
(Figs. 4, 6, 7 and 10). 
Each piece so separated from the chondriokont gradually moves up 
towards the apex of the inner zone, and during its passage increases in 
volume. At the same time its staining reaction changes, although this 
is not to be detected in sections stained with Haematoxylin. This ehange 
can be verified by reference to sections stained with Saffranin, where it 
will be seen that no granules are visible except in the upper two-thirds of 
the inner zone. 
It is therefore evident that during the passage of the granules from 
the margin of the two zones to the middle third of the inner zone, the 
mitochondrial staining reaction is retained, but after reaching the latter 
region, it is lost and is replaced by the saffranin staining reaction which 
is peculiar to the zymogen granules. 
Sometimes the pre-zymogen granules are not separated off from the 
proximal end of the chondriokonts, but the latter may detach off one or 
two long pieces, each of which again subdivides into pieces equal in size 
to the initial granules (Figs. 10 and 12 a). As the inner zone becomes more 
and more crowded with zymogen granules, the chondriokonts diminish in 
volume, (cf. Figs. 4 and 8) and are also not so strongly stainable as before 
x ) For the sake of convenience in description, that part of the chondriokont 
which is directed towards the base of the cell will in future be referred to as the distal, 
the other end, as the proximal extremity. 
