162 LACTIC ACID THE NORMAL ACID OF THE STOMACH. 
a faint precipitate, which was soluble in ammonia, took place. 
(This experiment has been repeated since, with the material 
discharged from the stomach, at will , after a meal of bread. 
The distillate became distinctly acid, but threw down the 
faintest precipitate, a mere opalescence, with nitrate of silver. 
The acid of the distillate gave all the evidence of lactic acid.) 
“ Experiment 2. — A portion of the material from the retort 
being tested with chloride of barium, gave no visible indica- 
tion of sulphuric acid. 
“ Experiment 3. — Another portion of the gastric fluid was 
heated in a porcelain capsule for the purpose of incineration. 
The vapour that escaped gave no evidence of acidity, but the 
residue became increasingly acid in proportion as it became 
more concentrated. 
May 9th. — Two ounces of bread moistened with water 
were introduced into the stomach, through the fistulous 
orifice. In an hour and a half the contents were withdrawn. 
The fluid was ve^ viscid, and presented, as before, a de- 
cidedly acid reaction. Some portions of the bread were 
undissolved, although the greater part had disappeared; 
sp. gr. not noted. The microscope revealed fewer epithelial 
cells than in the examination of the previous fluid, some 
mucous corpuscles and abundance of starch granules, some 
of which were broken down. 
“Experiment 4. — A portion of the fluid just obtained was 
decanted from the bread particles, and carefully distilled, 
without presenting any evidence of acidity to litmus in the 
fumes. The distillate was acid to litmus, and when tested 
with nitrate of silver, presented a very faint indication of the 
presence of hydrochloric acid. The residue in the retort, 
when somewhat concentrated, gave a deep acid reaction. 
66 Experiment 5. — A portion of the same fluid, as in Experi- 
ment 4, was gently boiled in a retort; the distillate was acid, 
and when tested as before, gave the same faint evidence of the 
presence of hydrochloric acid. The residue, when taken from 
the retort and examined w r ith litmus, was found more acid 
than before the distillation. It was then carefully evaporated 
and examined from time to time, with the effect of manifesting 
a constantly increasing acidity so long as it remained liquid. 
The heat was then carried still further, so as to dry but not 
char the material ; on moistening it with water, it was found 
even more intensely acid. Heat was again applied and 
carried to incipient charring, and then the material was 
moistened and tested again, exhibiting a diminished acidity. 
The same experiment, repeated and carried to increased 
charring, showed, on moistening the residue, a still diminish- 
