142 Imperial Institute of France. 
the determinations, even within 1 per cent. or perhaps 
more. 
It will hereafter be interesting to observe how far the ideas 
of the very ingenious Mr. Davy on the constitution of ni- 
trogen, and the many degrees of oxidation of its: pure base, 
will agree with these Jaws of nature. 
[fo be continued.] , 
XXV. Proceedings of Learned Societies. 
IMPERIAL INSTITUTE OF FRANCE FOR THE YEAR 1612, 
DRAWN UP BY M. CUVIER. 
[Concluded from p. 76.] 
Zoology, Anaiumy, and Animal Physiology. 
M. pE Montecne, a French physician, having discovered 
in himself a disposition to thraw up the contents of the 
stomach without inconvenience, conceived the idea of 
making use of the circumstance in order to elucidate se- 
veral particulars of the received doctrines on the subject of 
digestion. When he resorted to this practice with an 
empty stomach, he obtained a remarkable quantity of a 
liquid which he regards as a true gastric juice, and which 
he examined with reference to its chemical quantities, as 
well as with respect to its action on alimentary substances. 
M. de Montegre found this liquid to be very similar to 
saliva, but its action appeared to be very different from that 
described by Spallanzani. On exposing it to a temperature 
similar to that of the human body, in phials placed under 
the arm-pits, he saw it putrely, exactly like saliva. This 
juice only arrested the process of putrefaction in other sub- 
stances when it was naturally acid ; but by adding a little 
acetic acid to the saliva it acquired the same property. 
Besides, this acidity is not essential; and when M. de 
Montegre swallowed a sufficient quantity of magnesia to 
absorb it, digestion went on as usual. Acidity was repro- 
duced in a short time ;—even when M. de Montegre en- 
veloped with magnesia the food which he was eating, it 
soon became acid again. ; 
These experiments repeated a great number of times, and 
with every proper precaution, induced the author to con- 
clude that the gastric juice differs little if at all from saliva; 
that it cannot stop putrefaction, nor produce digestion, in- 
dependently of the vital action of the stomach ; and finally, 
that the acidity therein manifested, as well as that which is 
undergone 
