[Reprinted from The Medical News, July 28,1888. 
NOTE ON THE ACTION OF DIGESTIVE FLUIDS 
ON OIL. 
By H. W. WILEYTm.D., 
OF WASHINGTON, D. C. 
In a paper by Dr. D. W. Prentiss (The Medical 
News of May 12, 1888, p. 518), attention was called 
to the occurrence of so-called gall-stones in the de- 
jecta after the exhibition of olive or cotton-seed oil, 
and the substance of a preliminary study which I 
had made of the compositions of these bodies was 
given. At Dr. Prentiss’s request I have since col- 
lected additional data referring to this matter. 
The action of the gastric juice on fat seems to be 
confined to separating therefrom all connective and 
enclosing tissue and thus setting the fat free. It is 
found in the stomach in large globules and passes 
the pylorus unchanged. 
The pure intestinal juice seems to exert no action 
whatever on fats, and these substances are said by 
Busch to appear in the feces unchanged when sub- 
jected to the action of the intestinal excretions 
alone. 
Flint says that, while the action of the pancreatic 
juice in emulsifying fat is undisputed, there is no 2 
WILEY, 
evidence that in normal digestion there is ever any 
saponification. The fats found in the thoracic 
duct are always neutral, and do not contain any free 
fatty acid. On the other hand, Bernard has shown 
that the pancreatic juice outside of the body has a 
distinct power of saponifying fats. Landois and 
Stirling, however, recognize the saponifying power of 
the pancreatic juice in normal digestion, but attribute 
the result to a fat-splitting ferment called steapsin. 
The process of emulsification is said to go on with 
much greater rapidity when the fat in question con- 
tains a trace of free acid. The surface of each fat 
globule becomes coated with a thin film of soap, 
which is soon detached, carrying with it minute par- 
ticles of fat. The repetition of this process secures 
finally a complete emulsification. Both the soap 
and emulsion are absorbed. The authors state fur- 
ther that soluble fat soaps represent only a fraction 
of the fats which are absorbed, the greater part of 
the neutral fats being absorbed in the form of an 
emulsion. Absorbed soaps, however, have been 
found in the chyle. 
Buchheim, in his Lehrbuch der Arzneimittellehre, 
third edition, p. 370, says: “The pancreatic juice 
also possesses the property of dividing fats into fine 
particles, at the same time that it effects, by reason 
of a ferment contained therein, a partial saponifica- 
tion of them.” 
Edes ( Therapeutics and Materia Medica, p. 287) 
refers to the saponification of olive oil when admin- 
istered in large doses, and the excretion of semi- 
solid masses of soap. ACTION OF DIGESTIVE FLUIDS ON OIL. 
3 
What relation the saponification of fat in the in- 
testinal canal may have to its food value I cannot 
say. Recent experiments of Kellner (Zeitschrift fur 
Physiologische Chemie, vol. xii. p. 113) show that as 
a food for a draught horse one part of fat is equiva- 
lent to 2.6 parts of starch. Six and a half ounces of 
linseed oil enabled a horse to perform 464,000 
pounds more work in a day than without this food. 
Hoppe-Seyler (Physiologische Chemie, Part IV. p. 
949) ascribes the power of fat food to increase 
the amount of work performed to its influence in 
diminishing the consumption of the nitrogenous 
tissues. Whatever the true view may be, it seems 
certain that we have not yet quite understood the 
exact processes of fat-digestion and assimilation. 
Dastre, in a recent study of the action of the bile 
in fat digestion (Comptes Rendus, tome 106, p. 217), 
has shown that the pancreatic juice alone is not 
capable of digesting fats. These conclusions of 
Dastre have just been confirmed by the experiments 
of Prevost and Binet { Comptes Rendus of June 11, 
1888, p. 1690). These investigators find that in 
dogs, when the bile is prevented from taking part 
in digestion, fat foods are voided unchanged. 
By an artificial cholecysto-intestinal fistula in 
dogs, they caused the bile to be emptied into the in- 
testinal canal at a point twenty-five to forty inches 
from the duodenum. Through all this distance the 
fatty matters passed, subject to the action of the 
pancreatic secretion alone. The dogs being killed 
during the progress of digestion, the chylefers were 
examined. There was no trace of any absorption 4 
WILEY, 
of the fat until after the mingling of the bile with 
the contents of the canal. Whence Dastre con- 
cludes that the presence of both bile and pancreatic 
fluid is necessary to the digestion of fats. 
Dr. Prentiss, of this city, administered to a pa- 
tient a large dose (a pint) of cotton-seed oil. In 
the dejecta were found large numbers of moderately 
hard ovoid bodies, which the patient thought were 
gall-stones. They were brought to Dr. Prentiss, who 
preserved them in a stoppered bottle and sent them 
to me for examination. On reaching me the whole 
had melted to a viscous mass resembling soft soap. 
On examination it proved to be a true soap, a 
mixture of soap and free fatty acids, easily soluble 
in alcohol, yielding fatty acids insoluble in water 
on treatment with an acid. After saturation with 
hydrochloric acid the chlorides of the alkalies were 
separated from the‘fatty acids by filtration, evapo- 
rated to dryness, ignited to low redness to drive 
off any ammonia and to destroy organic matter; 
the residual chlorides were dissolved in water, fil- 
tered through a small filter, evaporated nearly to 
dryness, dissolved in alcohol and treated with pla- 
tinic chloride. A distinct precipitate of potassio- 
platinic chloride was formed, showing a trace of 
potassium. The chief part of the alkali, however, 
was soda, with, possibly, some calcium. This is an 
interesting case, showing the complete saponification 
or decomposition of a large quantity of oil by the 
pancreatic juice and bile, perhaps with the aid of a 
fat-splitting ferment, and the passage of the greater ACTION OF DIGESTIVE FLUIDS ON OIL. 
5 
quantity of soap and acids thereby formed unab- 
sorbed through the alimentary canal. 
Since the complete saponification of such an 
amount of oil would require more alkali than is 
normally found in the intestinal canal, it seems 
probable that the oil may be split up in the canal 
without complete saponification. I have, unfortu- 
nately, taken all the sample sent me for the first 
examination and therefore will not be able to decide 
this point until opportunity for another analysis is 
presented. 
The occurrence of semi-solid masses in the feces 
has been noted by many writers, but they have 
usually been called gall-stones. The Therapexitic 
Gazette for May, 1888, reports a case of this kind, 
but evidently without believing it true. As has 
already been noted, Dr. Edes has properly named 
these excretions, but informs me that he does not 
know'of any analysis of them having been made. 
Mojon (Revue Medicate, 1844, quoted in Thudi- 
chum’s Treatise on Gall-stones, p. 199) says, “con- 
cretions of solid fat occur in the feces after the use 
of sweet oil;” but in this he is evidently mistaken. 
Sweet oil could not produce a concretion of solid 
fat without undergoing a more profound change 
than saponification. These concretions were, doubt- 
less, masses of soap, such as I have described above. 
Thudichum (Treatise on Gall-stones, p. 135) de- 
scribes certain biliary calculi which were composed 
largely of calcium soaps. The hardness and crys- 
talline structure of these stones, however, would 
prevent them from being confounded with the 6 
ACTION OF DIGESTIVE FLUIDS ON OIL. 
masses of soap and acids forming the subject of this 
study. In the feces of dogs, Hoppe-Seyler (Physio- 
logische Chemie, p. 337) has found calcium soaps of 
stearin, palmitin and olein. The feces are exhausted 
with alcohol and ether, and the residue treated with 
hydrochloric acid and a mixture of alcohol and 
ether. Wegscheider {op. cit.) has found these cal- 
cium soaps, also, in the feces of healthy children 
who were nourished exclusively by mother’s milk. 
I desire to thank Drs. Prentiss, Edes and Lee for 
favors extended in the preparation of this note. 
Washington, D. C., July 3, 1888 THE MEDICAL NEWS. 
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