448 CHEMISTR Y OF THE DIGESTIVE PROCESSES. 
the production of fatty acid by pancreatic juice, although lie was the 
discoverer of this saponifying action. He states that, when neutral oil 
is shaken up with pancreatic juice, an instantaneous emulsion takes 
place; and, secondly, when neutral oil is submitted to the prolonged 
action of pancreatic juice, fatty acids are developed. Bernard con- 
sidered the formation of emulsion in the intestine as a more important 
process than saponification, due to a ferment action, and speaks of a 
"ferment emulsif." It is now certainly known that fatty acids are 
always formed in the intestine after the ingestion of fat, but an emulsive 
ferment is no longer believed in. The rapidity of fresh pancreatic juice 
in forming fatt} r acid is remarkable ; thus Eachford, 1 in very favour- 
able cases, found that a sufficient amount of fatty acid to form a spon- 
taneous emulsion (5"5 per cent.) is formed in presence of bile and 
hydrochloric acid at room temperature in two minutes. This very 
rapid action explains the error into which Bernard fell. 2 
Pancreatic jnicc obtained from a permanent fistula has less emulsive 
power than that from a temporary fistula ; it is also poorer in proteid, and, 
according to Kiihne, 3 the emulsive power does not depend upon the alkali, 
for faintly acid juice is capable of producing emulsion. Minkowski is of the 
opinion that it is chiefly to the proteid that emulsion is due, basing his 
opinion on the observation, made by Abelmann 4 in his laboratory, that after 
excision of the pancreas no fat except that of milk is absorbed ; unless minced 
pancreatic tissue be taken with the food, when other fats are also absorbed. 
These observations have been confirmed by Sandmeyer. 5 
Some observers ° hold that emulsification does not occur at all inside the 
intestine, and others " state that a considerable amount of emulsification takes 
place, but that the granules of fat in the emulsion are not nearly so small as 
those found in the chyle. 
Cash 8 found, in four experiments on dogs, that there was no emulsion 
in the intestine during active fat absorption. Moore and Rockwood, 9 in six 
out of sixteen experiments, obtained a similar result, but in the other ten 
experiments found emulsions in the intestine, containing fat globules of 
various dimensions, some of considerable size, but many exceedingly minute. 
These results indicate that in the dog at least, fats can be broken up and 
absorbed without undergoing previous emulsification. Still it should be 
borne in mind that these two different conditions of the intestine in the 
dog during fat absorption may be phases of the same process. The contents 
of the stomach are not discharged continuously into the duodenum, but from 
time to time the pyloric sphincter is relaxed, and a portion of the contents 
of the stomach ejected. It may well be that the condition of no emulsion is 
1 Joura. Physiol., Cambridge and London, 1891, vol. xii. p. 92. 
2 The statement that the fat-splitting action of the pancreatic enzyme is very slow, and 
hence that probably only a small percentage of fat is so decomposed in the intestine 
(see Bunge, "Lehrbuch," Anfl. 3, S. 175), undoubtedly arises from most observers using 
not pancreatic juice but pancreatic extracts, in which the easily decomposable fat-splitting 
enzyme was only present in traces. Rachford's results with pancreatic juice clearly indicate 
that the pancreatic secretion is capable within the time of digestion of a fatty meal of 
decomposing all the fat into fatty acids and glycerin. 
3 "Lehrbuch d. physiol. Chem.," 1S68, S. 122. 
4 Inaug. Diss.. Dorpat, 1S90. 
5 Ztschr.f. Biol., Miiuchen, 1895, Bd. xxxi. S. 40. 
6 Cash, Arch.f. Anat. u. Physiol, Leipzig, 18S0, S. 323; Altmann and Krehl, ibid., 
1889, Anat. Abth., Supp. Bd. S. 86 ; 1890, Anat. Abth., S. 97. 
7 Heidenhain, Arch.f. d. yes. Physiol., Bonn, 1888, Supp. Heft, Bd. xliii. S. 88. 
Other recent observers who describe an emulsion in the intestine are, Lebedeff, Arch.f. 
Anat. u. Physiol., Leipzig, 1883, S. 504 ; Lewin, Arch.f. d. ges. Physiol., Bonn, 1896, Bd. 
lxiii. S. 180! 
8 Loc. ait. 9 Joum. Physiol., Cambridge and London, 1897, vol. xxi. p. 74. 
