440 CHEMISTR Y OF THE DIGESTIVE PROCESSES. 
after its removal from the body, and proved that the peptone remained 
unchanged. Also, when a small quantity of peptone or albnmose was 
slowly injected into a mesenteric vein, this was not assimilated, but 
appeared afterwards in the urine, showing that it had not been altered 
by the liver. Shore x circulated peptone not only through the liver, but 
through the spleen also, by injecting into a splenic artery, and arrived at 
similar results ; practically, all the peptone appeared again in the urine 
unchanged. 
These results show that the albnmose and peptone do not even enter 
the portal circulation as such; the only remaining place where they can 
undergo modification is in the wall of the intestine itself, and the 
following experiments show that this is the seat of change. 
Ludwig and Salvioli 2 separated a loop of intestine in the dog with 
the attached portion of mesentery, and injected a gramme of albumose and 
peptone in 10 per cent, solution, ligaturing the piece of intestine at both 
ends. The piece of isolated intestine was maintained alive by circulating 
through it warm defibrinated blood diluted with normal saline, by means 
of a cannula inserted into that branch of the mesenteric artery which 
had supplied the loop (anastomosing arterial branches being excluded by 
ligatures), the blood, after circulating, flowing away by the corresponding 
branch of the mesenteric vein. After four Ik airs of perfusion in this manner, 
the piece of intestine and the defibrinated blood having been all the time 
maintained at the body temperature, the remaining contents of the intes- 
tine and the circulating fluid were examined for albumose. The intestine 
contained about half a gramme of coagulable proteid, and only traces of 
albumose, while the defibrinated blood contained no albumose whatever, 
Therefore the albumose must have disappeared in the intestinal wall. 
Hofmeister 3 investigated the organs of dogs killed during proteid 
digestion as to their content of albumose, and found it present in the 
mucosa (only) of the stomach and intestine, as well as in small quantities 
in the blood, and in four out of ten cases in the spleen ; in the other 
organs it was entirely absent. He also showed experimentally that this 
albumose underwent a rapid change. 
A fresh stomach was divided into two symmetrical halves, or a piece of 
small intestine longitudinally into two similar pieces. 
The surface of the mucous membrane was washed clean with saline, then 
one of the two pieces in each case was thrown immediatel}' into boiling water, 
while the other was similarly treated after being first kept for some time in a 
moist chamber at 40° C. More peptone was always found in the first piece 
than in the second, and when the second piece had been kept for a sufficient 
time (1 to 2 hours) at body temperature, previous to placing in boiling water, it 
was found to contain no albumose whatever. In another experiment, while 
one piece Avas thrown, as before, immediately into boiling water, the second was 
thrown for some minutes into water at 60° C, and then kept as before at 40° 
C. for two hours; the result now obtained was that both pieces contained an 
equal amount of albumose. Since most enzymes would not be affected by such 
a preliminary treatment, while living cells would be destroyed, this indicates 
that the cells of the mucosa do not owe their activity to contained enzymes. 
1 Journ. Physiol., Cambridge and London, 1800, vol. xi. p. 559 ; VerhancU. d. X. 
internal, meal. Cong., Berlin, 1891, Bd. ii. Abtli. 2, S. 31. 
2 Arch.f. Anat. u. Physiol., Leipzig, 1SS0, Supp. Band, S. 112. 
3 Ztschr. f. physiol. C'hcm., Strassbm-g, 1882. Bd. vi. S. 51; Arch. f. earner. Path. v. 
Pharmakol., Leipzig, 1885, Bd. xix, S. 8, 
