ACIDITY IN STOMACH 233 
The contents should be carefully filtered and the following deter- 
minations made. 
Total Acidity. Filter 10 c.c. of the gastric contents and add about 
four drops of phenolphthalein. Titrate to a faint pink color with 
N/10 NaOH. Calculate the number of cubic centimeters of N/10 
NaOH required for 100 c.c. of stomach contents. This is often termed 
degrees. Some prefer to express the results in terms of per cent hydro- 
chloric acid. (1 c.c. of N/10 HCl=.00365 gm. HCl.) 
Free Acidity. This gives both the organic and inorganic free acid. 
Titrate 10 ¢.c. of the stomach contents with N/10 sodium alizarine 
sulphonate as the indicator. Titrate to a violet color. Determine 
and report the number of cubic centimeters of N/10 NaOH required 
by 100 c.c. of the juice. 
Combined Acidity. The difference between the total acidity and 
the free acidity is the combined acidity. This is also reported for 100 
c.c. of the stomach contents. 
Detection of Lactic Acid. Prepare Uffelmann’s reagent by adding 
ferric chloride to a 1 per cent solution of phenol until a blue color results. 
Add 3 ¢.e. of this solution to 3 ¢.c. of the stomach contents. The pres- 
ence of lactic acid will be indicated by the formation of a yellow color. 
Organic Acids and Acid Salts. Subtract the free hydrochloric acid 
from the combined acidity and express the results in terms of 100 c.c. 
of gastric contents. 
Microscopical Examination. This may yield much valuable infor- 
mation. The microorganisms to be expected are yeasts, mold spores, 
rods and sarcine. Other bacteria may be present under certain con- 
ditions. Other particles, such as cellulose epithelial cells, starch grains, 
etc., may also be present. 
Bacteria in Intestines and Feces. The bacteria which gain entrance 
to the intestines and feces are those which have passed through the 
stomach in the chyme or which may have been contributed, in rare cases 
from the blood stream. 
Relation of Bacteria to Life. This has been a much-debated ques- 
tion. Pasteur (1885) believed that bacteria were essential for normal 
life. Nuttal and Thierfelder (1895, 1896 and 1897) reared guinea pigs 
under aseptic conditions which had been delivered by Cesarian section. 
These increased in weight, but not as regularly as normal pigs. From 
these data, the authors concluded that bacteria were not necessary. 
Schotellius (1899, 1902) hatched chickens in a sterile environment and 
from the data which he secured concluded that chicks could not live 
in absence of bacteria. He stated also that sterilizing the grain may have 
