1898 - 99 .] Prof. Carlier on Changes in Newt’s Stomach. 687 
movement of the chromatin towards the nuclear membrane and 
its application to its inner surface is of service in facilitating 
this process ; but I further believe that the prozymogen is not 
elaborated into zymogen until the cells have practically emptied 
themselves of the zymogen already produced, and have begun to 
take up substances from the blood. Once this has occurred, the 
cell quickly transforms the prozymogen into new zymogen, which 
is the meaning of the rapid reappearance of the zymogen granules. 
On the other hand, the power of the nucleus to manufacture 
prozymogen is limited, and once its store of chromatin is reduced 
to a certain point, it must renew the stock before it can again pro- 
duce prozymogen, and that this renewal of chromatin is brought 
about by the entrance into the nuclear juice of an easily coagulable 
substance (probably a proteid material amongst other things), 
which is the meaning of the great increase in the lanthanin 
granules soon after complete exhaustion of the nucleus has 
occurred, and I believe that this necessity for repair sufficiently 
accounts for the phenomenon of the double secretory wave, the 
cell, though full of zymogen granules, not being in a fit state to 
secrete again until the nucleus is completely recuperated • but that 
when once this point is reached, there being no longer any further 
need of rest, the cell again starts secreting should any call be made 
upon its energies. 
I have, therefore, been able to supply the link in the chain that 
seems to have been missing in the work of previous investigators, 
namely, the observation above recorded of an absolute diminution of 
chromatin occurring as a result of the production of prozymogen. 
Chromatin contains nucleic acid and an albuminous substance • it 
is very stable, and acts as an acid to bodies less acid than itself ; 
therefore it stains with methyl-blue. In order that this stable 
body may pass into the cytoplasm it must be rendered soluble 
(there being no evidence of its passage bodily out of the nucleus) ; 
in this process some of the albumin is removed as effete material 
that goes to form the nucleolus. This albumin acts as a base in 
presence of bodies more acid than itself, and therefore exhibits 
marked affinity for the eosine. Being now useless in the nucleus 
it is extruded into the protoplasm, there to be disposed of. The 
more acid part of the chromatin passes into the cytoplasm, where it 
