/ '///•; INTESTINAL ENZ YMES. 34 1 
extractives concentrate 1 solutions of different salts. He found that some salt 
solutions extracted all three ferments, while others especially extracted one 
ferment accompanied by traces of the others. Thus sodium chloride, sodium 
sulphate, and potassium chlorate extracted all three ferments indifferently; 
sodium bicarbonate, with a little of the normal carbonate added, extracted best 
the fat-splitting ferment ; the proteolytic ferment was taken up best by 
potassium iodide, arsenite, or sulphite ; and the diastatic ferment by 
potassium arsenate alone or with the addition of ammonia. 
Dastre l has recently described methods for approximately separating the 
proteolytic and diastatic enzymes of the pancreas. 
1. If the pancreas of an animal killed during digestion be cut into large 
pieces, and these then digested for 15-20 minutes at 40° C, in normal saline 
(•7 per cent.), the filtrate is found to possess a strong diastatic action, but 
scarcely any proteolytic action. If, after this first extraction, the pieces are 
finely minced and extracted anew with normal saline (1 per cent, of sodium 
fluoride being added to prevent putrefaction), an extract is obtained rich 
in proteolytic ferment, but containing scarcely any diastase. 
2. On extracting a fresh gland with alcohol of increasing strength, after- 
wards with ether, and drying over sulphuric acid, a powder is obtained 
which yields, on extraction with saline, a fluid which is almost inert towards 
starch, but is actively proteolytic. 
3. An extract made from the pancreas of an animal Avhich has not been fed 
for some days, contains proteolytic ferment but has scarcely any diastatic action. 
The Intestinal Enzymes. 
Practically nothing is known of the enzymes of the small intestine 
save their action on foodstuffs ; none of them have been obtained in 
even approximately pure condition, and the fact that there are enzymes 
rests on the observations — (1) that the action is destroyed by boiling, 
and (2) that it takes place under antiseptic conditions. Until the 
importance of this latter condition was demonstrated by the work of 
Kiihne on pancreatic digestion, there was much difference of opinion 
as to whether the succus entericus contained a proteolytic enzyme 
or not ; some observers had observed digestion of proteids by this 
fluid, and others had been unable to do so. At length it was shown 
by Masloff 2 and by Wenz 3 that when precautions are taken to 
prevent bacterial growth, the succus entericus or extracts of the 
intestinal mucous membranes have no action on proteids or on 
albumoses. 
With regard to the action of succus entericus on carbohydrates, the 
more recent work on the subject all goes to show that starch is con- 
verted into maltose, maltose into dextrose, and cane-sugar into dextrose 
and kevulose, both by the succus entericus and by extracts of the 
intestinal mucous membrane. 
The succus entericus contains no enzyme which acts on neutral fats. 
The power of emulsifying fats, which was occasionally observed by the 
earlier workers on the subject, was doubtless due to the alkalinity of the 
1 Compt. rend. Soc. de bio!., Paris, 1893, tome xlv. p. 648 ; Arch, dephysiol. norm, et'path., 
Paris, 1893, tome xxv. p. 774. 
2 Untersuch. a. d. physiol. Inst. d. Unir. Heidelberg, 1882, Bd. ii. S. 920. Masloff 
found very slight action of the juice when acidified, probably due to infiltrated pepsin. 
3 Ztschr. f. Biol., Miinchen, 1886, Bd. xxii. S. 1. This result is confirmed by the 
observations of Tubby and Manning on human succus entericus, Guys Hosp. Rep., London, 
1891, vol. xlviii. p. 277. 
