EXPERIMENTS ON DIGESTION. 285 
character than when the stomach had not been thus irritated. This 
was more confirmed by the action of pepper on the stomach of a 
dog that had been fasted. The animal was made to swallow a small 
quantity of pepper, and, on his being destroyed, the mucous mem- 
brane of the stomach was of a deep red colour, and furnished nearly 
ten grains of a greyish white liquid, a little turbid, of a slight salt 
taste and an acid smell, and which deeply reddened the tincture 
of turnsol. 
As the saliva of a dog is not acid, it is evident that the liquid 
contained in this irritated stomach was not the fluid which he 
had swallowed, because it reddened the turnsol. We could not 
consider it as any secretion from the oesophagus, for that canal was 
very slightly humid both in the dogs and the horses which we had 
compelled to swallow the pebbles ; and the slight portion of fluid 
that we could collect, transparent and slightly mucous, would 
not redden the turnsol. Yiridet had previously remarked that 
the oesophagean secretion was not acid*. It results from this that 
the physiologists who deny the existence of the gastric juice as a 
peculiar fluid are in error. 
If any one asks, what are the sources or the secretory organs of 
the gastric juice, we reply that it is exceedingly probable that the 
liquid portion of this juice is derived from the arterial capillary 
reservoirs of the mucous coat of the stomach — that which is not 
covered by a kind of epidermis : and that the portion of greater 
consistence — ropy and mucous — is secreted by the mucous folli- 
cular glands which are so numerously spread over this viscus. 
Blasius and Yiridet have already demonstrated the existence of 
numerous glands in the stomach of the dog and other animals. 
Everard Home has described and figured these glands as he saw 
them in many carnivorous and herbivorous animals. In the ass 
and the horse they are only found in that portion of the stomach 
which is not covered by the cuticular coat. 
However, it is difficult if not impossible to establish any thing 
positive with regard to the liquid or mucous portion of the gastric 
juice, because we are not able to observe the secretion of it in the 
stomachs of living animals. 
Chemical Composition of the Gastric Juice . — A great number of 
physiologists — ancient and modern — -Wepfer, Yiridet, Rast, Reau- 
mur, Spallanzani, Scopoli, Stevens, Carminati, Baugnatelli, Yau- 
quelin, and others, have striven hard to discover this, but their 
researches have not terminated in any satisfactory result. There is 
no animal fluid with regard to the properties of which chemists and 
* Tractatus novus medico-physicus de prima costione,prcecipueque de ventri - 
culi fermento , Geneve, 1692. He found that the oesophagean secretion in a 
pig would not act on the tincture of turnsol, while that from the stomach 
deeply reddened it. 
