872 
Supphmeni to the ^'Tropkal AgncuUurisi:' [June 1, 1903, 
Suppose, for instance, that 1-5 per cent of the 
protein in a specimen of bread is excreted, then 
Bo per cent remains for the use of the body. If 
the bread has 8"4 per cent of protein, 100 pounds 
will have 8*4 pounds, of whicli 85 per cent or "'l 
pounds will be utilized by the body. 
The terms digestible, indigestible, etc., as here 
used refer simply to the food which is or is not 
available for the general nourishment of the 
body after the process of digestion is completed. 
In common parlance, however, they are used more 
loosely as referring to the ease and quickness of 
digestion, and to the general healthf ulness of 
food. One kind of food, bread, for instance, is 
Spoken of as "simple" and ."digestible," and 
another, like fruit cake, as " rich " and " indigest- 
ible." There is often much practical truth behind 
such statements, though little is defluitely known 
concerning the time or labour required to digest 
different kinds of food. 
Among the earliest and most famous experi- 
ments concerning the time required for digestion 
in the stomach are those made by Dr. V/illiam 
Beaumont, U. S. A,, between 1825 ojnd 1833. 
His subject was a French-Canadian trapper, a 
man quite normal except for an aperture through 
the abdomen into the stomach made by a gun- 
shot wound, and closed only by a valve whicli 
had developed over it. By pressing the valve 
inward the contents of the stomach could be 
observed or removed at will, thus affording ex- 
cellent opportunity to study the action of 
the gastric juice. Dr. Beaumont fed the man 
on various diets, and noted the different con- 
ditions accompanying each. The book in which 
he describes his experiments f contains a table 
of the average time required for the stomach 
to digest various articles of diet, from which 
many of the statements still current concerning 
the relative digestibility of different foods are 
taken. 
One of Dr. Biaumont's general deduciious was 
that most of the common foods required from 
2 to 4 hours. He says further : 
"Tlie time required for the digestion of food is 
various, depending upan the quantity and quality 
of the food, state of the stomach, etc., but the time 
ordinarily required for the disposal of a moderate 
meal of the fibrous parts of meal, with bread, etc., 
is from 3 to hour?." 
Valuable and interesting as Dr. Beaumont's 
book undoubtedly- is, its conclusions cannot be 
taken as final, because he does not state the 
amounts of food consumed, The science of nutri- 
tion in Its development has also shown many 
errors in the reasoning. It should in justice be 
said that Dr. Beaumont recognized the fact that 
his experiments had to do only with digeeLion 
in the stomach, or " cliymificaLioii," as he terms 
if. Fnrthermore, his experiments have been of ten 
misquoted and given a different interpretation 
from that which he intended. 
Food does not ordinarily pass from the stomach 
into the intestine until it has been reduced to a 
liquid or semi-liquid condition. The length of 
time required for different foods to leave the 
stomach has been recently studied by Peuzoldt» 
with healthy men. He u«ed a stomach tube for 
removing the stomach contents for examination, 
lie found that the amoutit and consistency of 
food have a marked influence on the rate of 
digestion in the stomach. Fluids leave the 
stomach more rapidly than other materials. I'rom 
6 to 7 ounces of water or other common beverage? 
leave the stomach in 1^ hours. Seven ouuces°of 
boiled milk leave the" stomach in about 2 hours. 
Hot drinks do not leive the stom ich more quickly 
than cold ones, nor does the qumtity have much 
effect. Solid matter in solution or suspension 
delayed the passage of fluid from the stomach 
sorceu'hat. The consistency of solid foods thus 
seems to have more effect upon digestibility than 
the amount consumed. The quantity eaten in- 
creases the length of time the material remains 
in the stomach, but not proportionally. 
To select a few examples of the time required 
for foods to leave the stom ich : Tsvo eggs (^rav,-, 
poached, or in the form of an omelet), 7 ounces 
sweetbreads, 10 moderate sized oysters, 7 ounces 
white-flsh or 3^ ounces of white bread, cauli- 
flowers, or cherries, each left the stomach in 2 to 
3 hours. Eight and one-fourth ounces of chicken, 
9 ounces of lean beef, 6. ounces boiled ham, 3-k 
ounces roast veal or beefsteak, 5|- ounces of 
•coarse bread, boiled rice, carrots, spinach, radish, 
or apple, left the stnuach in 3 ti 4 hours, Nine 
ounces of smoked tongue, 3|r ounces smoked beef, 9 
ounees ro ist goose, 5J ounces string beans, or 7 
ounces peas porridge, left the stomach in 4 to 5 
hours. 
Generally speaking, the most readily digested 
animal foods were materials of soft consistency. 
White meats — for example, chicken— leave the 
stomach more quickly than red meats or dark meat 
—for instance, duck. The method of cooking also 
exerts a very marked influence on stomach 
digestion. Fresh fish was found to be more readily 
digested than meats. 
Aa regards vegetable foods in general, the con" 
sistency and the amounts of solid material wer^ 
again the principal factors affecting the time 
required for digestion in the stomach. Mealy 
potatoes, for instance, were more easily digested 
than waxy potatoes, and mashed potato more 
readily than potato cut up in piece=. Fine breap 
was more quickly digested than coarse bread. 
There was not much difference in the time 
required for bread crust, bread crumb, toast, 
new bread, and stale bread to digest in the 
stomach, provided all were equally well chewed' 
It must' be remembered that digestion con- 
tinues in the intestine, and that the total time 
required for the digestion and absorption of the 
nutrients in any given food material is not shown 
by such experiments. They find their chief 
application in prescribing a diet for invalids, as 
in. such cases it is often desirable to require of 
the stomach only a limited amount of work. 
Digestibility is often confused with another 
very different thing, namely, the agiveing or 
disagreeing of food with the person who eats it. 
Daring the process of digestion and assimilation 
the food, as we have seen, undergoes many 
