RB. KR. Bensley _ 149 
It is being softened by the action of the saliva and of the secretion of 
the cardiae glands, subjected to the action of bacterial enzymes, and, 
after it has passed the cardiac zone, to the digestive action of the gas- 
tric juice; it is being converted into a softer and more plastic mass. In 
view of these changes, the fact to which Oppel has called attention that 
the distribution of the food masses in Ellenberger’s diagram corre- 
sponds almost exactly with the areal subdivision of the mucous mem- 
brane, is not without significance. 
The newly-swallowed food is contained in the portion of the stomach 
which is lined by stratified epithelium, the cardiac gland region is occu- 
pied by food which has already undergone some maceration and soften- 
ing, and the fundus and pyloric gland zone contains food in which the 
softening process has reached its highest degree. I can see no other 
explanation for these circumstances than that the changes have been 
primarily due to the mechanical action of the food on the mucous mem- 
brane, and that the rapidity of their production in any region bears a 
direct relation to the consistency of the food that is contained in that 
region. This mechanical effect would be in part due to friction owing 
to the unusual consistence of the food, but doubtless other factors play 
an equally important part. Among these, over-distention of the stom- 
ach, owing to the greatly increased bulk of the food as compared with 
that of animals such as carnivora which subsist on a more concentrated 
diet, is of the first importance. This distention is in placental mammals 
most prominently displayed in the fundus sac, the portion where histo- 
logical changes first appear. Another factor of importance is the pro- 
longed stay of the food in the stomach owing to the increased bulk, 
unfavorable consistence and reduced digestibility. A fourth factor 
which may possibly play a considerable réle in aquatic animals with a 
reduced dentition, is the reduction of the temperature in the mucous 
membrane due to the rapid ingestion of considerable masses of food of 
lower temperature than the body. 
That such conditions may be the cause of profound changes in the 
mucous membrane of the stomach is indicated by the recent study by 
Cade, o1, of the histological changes in the mucous membrane of the 
cat’s stomach due to a gastro-enterostomy. In this experiment the cat’s 
stomach was divided completely into two portions, one containing the 
fundus zone and the other the pyloric zone, and the cut ends closed by 
suture. An anastomosis was then effected between the greater curva- 
ture and a loop of the ileum. After a lapse of six months the animal 
was killed and the stomach examined, with the result that the mucous 
membrane was found to have undergone changes in the neighborhood of 
