442 CHEMISTRY OF THE DIGESTIVE PROCESSES. 
and for the mechanical stimulation its presence gives to the intestinal 
movements. 
The small amount of vegetable proteid absorbed, compared with that 
of animal proteid, is in part due to the envelope of indigestible cellulose 
by which it is surrounded, in part to the shorter stay in the intestine 
due to its action in causing increased peristalsis, and in part to its own 
less digestible character. 
The percentage of various kinds of plant proteid absorbed also varies 
considerably : thus the proteids of some leguminous plants and cereals are 
absorbed nearly as perfectly as those of animal origin, while in most 
others (potato, lentil) it is much less complete (22 to 48 per cent. less). 
The percentage of the nitrogen of meat or egg appearing again in 
the fseces in man, only amounts to 2*5 to 2 - 8 per cent., that of milk to 
6 to 12 per cent. 
Considerable tracts of the alimentary canal can be removed or 
thrown out of action without causing the death of the animal or even 
causing serious impairment in absorption. 
The stomach was first removed by Czerny l in dogs: one animal 
was preserved alive after such an operation for live years; in the course 
of two months after the operation it recovered to quite a normal con- 
dition, and ate, digested, and absorbed all kinds of food. It was finally 
killed for examination by Ludwig and Ogata, and the dissection 
showed that only a very small portion of the cardiac end of the stomach 
remained. 
Ludwig and Ogata' 2 further investigated the course of digestion and 
absorption when gastric digestion is excluded, by anotheT method. They 
made a fistula beyond the pylorus and inserted into the beginning of the 
duodenum a small thin rubber ball, attached to a rubber tube, by means 
of which it could be distended with water under pressure, so as to 
occlude the intestine from the stomach. In this way gastric juice could 
be prevented from entering the duodenum, and by feeding from the 
fistula the effect of intestinal digestion alone be studied. The food was 
usually completely digested and absorbed, and the faces presented a 
normal appearance. Raw meat was digested much more efficiently than 
boiled, connective tissue was not so completely digested as in normal 
dogs, but nevertheless two injections of meat per diem sufficed to keep 
the animal in equilibrium. 
The stomach has also recently been removed in d< >gs 1 >y F. de Fillipi, 3 
who found no disturbance in metabolism and no increase in intestinal 
putrefaction in spite of the absence of hydrochloric acid. 
The same experimenter also removed in a bitch T9 metres of the 
small intestine (almost the entire length), and found no metabolic 
disturbance, except that the absorption of fat was diminished : the animal 
lived, and afterwards brought up a litter of pups in this condition. 
The author suggests that the large intestine here vicariously took on the 
absorptive functions of the small intestine. 
Complete or partial extirpation of the pancreas, or ligature of its 
duct, causes more or less disturbance of proteid digestion and absorption, 
but not so much as might be expected, in view of the most important 
proteolytic function of the secretion of this gland. 
1 " Beitriige z. operativen Chirurgie." Stuttgart, 1S7 S . S. 141. 
2 Arch. f. Anat. u. Physiol, Leipzig, 1S83"S. 89. 
3 Deutsche med. Wchnschr., Leipzig, 1894. Xo. 40, S. 780. 
