ROYAL VETERINARY COLLEGE. 647 
small quantity of this acid free in the stomach. Others contend 
that it is the lactic acid, the result of a change induced in the 
amylaceous matters by the contact of caseine, and which for a 
long time was confounded with the acetic ; but very lately, 
M. Blondlot has asserted that the acidity of the stomach is 
owing to the presence of the biphosphate of lime , obtained by 
the action of common salt on the phosphate of lime existing in 
the blood. This he shews by the following DIAGRAM : — 
Neutral phosphate lime. + Hydrochloric acid. 
2 Ca Oj P 0 5 H. Cl. 
= Biphosphate lime. -f- Chloride calcium. + Water. 
Ca O P 0 5 Ca. Cl. H. O. 
The soda, he states, is retained by the blood. 
Liebig is of opinion that the most active agent, effecting 
the most important changes in the food in the stomach, is a 
principle designated PEPSIN, formed by the action of the oxygen 
taken in with the saliva on the epithelium of the mucous mem- 
brane of this organ. The action induced is termed CATALYTIC, 
or decomposition by contact. A change constantly taking place 
in nature, and due to the presence of a certain class of bodies 
called ferments, which are universally distributed. Thus, in 
vegetable fermentation the gluten is transformed into a prin- 
ciple denominated diastase, which sets up those molecular trans- 
mutations that characterise the change there going on. 
Dr. Thomson, speaking of digestion, says, and says truly, 
“ the most superficial observer must have noticed that digestion 
is something more than a mere chemical action, and * * * 
“ I regret,” he adds, “ to be obliged to infer that the commonly 
received view of it is scarcely admissible. It is, perhaps, safer 
to conclude that there is a deficiency of knowledge on this 
important subject; and that not only do we require to possess 
a few facts additional before we can be said to understand the 
process, but we want an entirely new basis on which to found 
a theory of digestion.” He conceives that the starch of food 
is first coverted into sugar, and this again into simpler forms, 
as alcohol and acetic or lactic acid ; this last being most com- 
monly found by him in the stomach to the exclusion of the 
hydrochloric. The digesting principles, called pepsine, gasterose, 
&c. he considers to be albumen modified by the action of sol- 
vents. The process itself he rather refers to some nervous 
action, as Dr. Wilson Philip, indeed, had done before him ; who 
considered electricity conveyed by the gastric nerves to be the 
operating cause. 
The acid chymous mass is now passed onwards into the 
duodenum, and here it meets with two secretions, both of which 
