iv DIGESTION IN THE INTESTINE 259 



the cells of Blastomycetes and Hyphomycetes which develop in 

 gastric juice, like the cells of highly acid plant organs which 

 perish in an alkaline medium. 



An experimental illustration of the theoretical conclusions of 

 Fermi and Matthes was put forward by one of Fredericq's pupils, 

 Paul Otte, in 1896. He sought to elucidate the comparative 

 value of the epithelium as a protective organ of the subjacent 

 tissue. With this object he isolated a loop of intestine in the 

 dog, washed it with physiological saline, and then introduced 

 active gastric, or equally active pancreatic juice, kept in the 

 cavity by means of two ligatures at the extremities of the loop, 

 and stitched up the abdominal wall. After 5 to 8 hours the 

 animal was killed, and the changes produced by the digestive 

 juices in the loop examined, either by simple inspection or with 

 the microscope. His results briefly described are as follows : 



(a) Neither pancreatic nor gastric juice is capable of attacking 

 the normal mucous membrane of the intestine, although this is 

 not, like the gastric mucous membrane, inured to the presence 

 of free hydrochloric acid. This result is identical with that 

 obtained by Gaglio on the bladder, and probably lends itself to 

 the same interpretation. 



(&) If before introducing one or the other of the digestive 

 juices, the loop of intestine is washed for a short time with 2 per 

 cent silver nitrate solution, and then with 0'6 per cent sodium 

 chloride, no digestive alteration is produced, although the epi- 

 thelium which covers the tips of the villi is altered and killed 

 by the action of the caustic. Nor does the injection of 0'05 per 

 cent sodium fluoride solution produce any sign of digestion in the 

 loop, although it completely alters the osmotic and absorbent 

 power of the mucosa without destroying the epithelium. These 

 results can be explained neither by the theory of Gaglio nor by 

 that which attributes an exclusively protective function to the 

 epithelium. 



(c) If before introducing the digestive fluids into the loop, the 

 blood-vessels running to it are tied, auto-digestive phenomena 

 make their appearance rapidly. Since mere ligation of the vessels, 

 without introducing digestive fluids, produces no clear symptoms 

 of necrobiosis in the intestinal epithelium after eight hours, we 

 are forced to conclude that ligation, by altering the nutrition of 

 the mucosa, disposes it to become saturated with the solvent fluids 

 to which it is normally refractory. The auto-digestive lesions 

 common in the stomach and intestine of patients who have died 

 after a long illness, are also due to the bad nutrition and enfeebled 

 resistance of the mucous membrane to the digestive action of the 

 pancreatic juice. 



As a whole, the phenomena which we have been discussing 

 show the resistance of the living protoplasm to the attacks of the 



