702 
MR. J. N. LANGLEY ON THE HISTOLOGY AND 
which has been converted into granules. Clearly were this the case the cell would be 
very much smaller than it is. 
Further, in the first stage of digestion the cells increase in power of staining with 
carmine and other similar reagents. This is only what has been shown to take place 
by Heidenhain and others in a great number of gland-cells. The increased staining 
power is usually considered a proof of the increase of protoplasm. From this, too, then 
we should conclude that the protoplasm is growing, although the cells are diminishing 
in size. 
There can, I think, be little doubt that these three processes also go on simultaneously in the serous 
glands during secretion. The increased staining power of the cell with carmine indicates that fresh 
protoplasm has been formed. I have previously shown that a using up of granules takes place. If we 
grant, as from analogy I think we may, that the granules give rise to the organic substances in the 
secretion, it would, as in the gastric glands, appear unlikely that these substances should be formed from 
the cell-protoplasm, otherwise than through the intermediate step of grauules. But from this I think it 
follows that the granules are formed during secretion as well as in rest, for with a corresponding amount 
of solids excreted, the visible diminution in the number of granules is less in the sub-maxillary than in 
the parotid of the Rabbit, so that more new granules must have been formed by the sub-maxillary gland- 
cells than in the parotid. Further, the total amount of organic solids obtainable by protracted stimulation 
of the secretory nerves of the parotid seems to me too great to allow them to be referred to the granules 
present to start with. 
Some remarks on the difference of rate with which the above-mentioned three processes 
go on in the gastric glands, according as the animal is fed ivith digestible or with 
non-digestible food . 
If we compare the granular content of the gastric gland-cells at different periods 
after an animal has been fed with worm, with the granular content at different periods 
after an animal has been fed with sponge, we find that the main point of difference 
is that in the latter case the diminution in the number of granules lasts much less 
time, but is, during that time, much more rapid. 
The explanation of the appearances which accompany sponge-feeding seems simple ; 
the stimulation causes a slow nett using up of granules ; after about twenty-four hours 
the stomach becomes accustomed to the presence of the sponge, and the stimulation 
becomes less and less ; as the stimulation becomes less the tendency of the cells to form 
granules gets the upper hand of the using up of the granules, and they slowly increase. 
In the worm-fed animal we have to account for the more rapid using up during the 
first hours of secretion, and the more rapid formation during the last hours of secretion. 
Heidenhain has shown that in the Mammal the presence of digestible food causes 
a more rapid flow of gastric juice than the presence of noil-digestible food. He 
referred this to a chemical stimulation caused by the absorbed products of digestion. 
The same explanation will probably serve here. It seemed not unlikely that the 
peptone formed might be the particular product causing increased secretion. I have 
made some experiments upon the effect of injecting peptone into the lymph-sac and 
