298 PHENOMENA OF PUTREFACTION. 



effected in the small intestine on the one hand and in the colon 

 011 the other, in man. On issuing from the stomach where, by 

 the action of the pepsin and hydrochloric acid secreted hy the 

 gastric glands, a more or less extensive peptonisation of the diges- 

 tible albuminoids in the food has been effected the pulpy food, 

 now known as chyme, has a strongly acid reaction (equivalent 

 to 0.1-0.3 P er cent, of hydrochloric acid). Immediately on its 

 arrival in the upper division of the alimentary canal (small intes- 

 tine), it becomes mixed with bile and pancreatic juice, under the 

 influence of which the fat is emulsified and the insoluble carbo- 

 hydrates (starch) are hydrolysed. Both secretions have an alkaline 

 reaction, which, however, is not sufficiently strong to immediately 

 neutralise the acidity of the contents of the intestine. This 

 slightly acid nutrient medium, rich in sugar, offers a favourable 

 field for the activity of the lactic acid and allied bacteria intro- 

 duced along with the food; and, moreover, the acidity restricts 

 the development of the competitive putrefactive bacteria. In 

 proportion, however, as the contents of the intestine are forced 

 onward and approach the colon, the acid reaction is neutralised 

 by the alkaline mucus secreted by the intestinal glands. At the 

 same time the composition of the mass has become changed, since 

 the products of the hydrolysis of starch, which have also to some 

 extent been converted by the aforesaid bacteria, have been absorbed 

 into the blood-vessels. Therefore in the contents of the colon it 

 is the (undigested or indigestible) albuminoids and biliary con- 

 stituents which are decomposed by the putrefactive bacteria now 

 coming into action, and it is here that the malodorous products 

 (indole, skatole, volatile acids, sulphuretted hydrogen, &c.), to 

 which the intestinal contents (finally issuing from the rectum as 

 faeces) owe their repulsive smell, are produced. 



The researches of MACFADYEN, NBNCKI, and SIEBER (III.) 

 revealed both the actual course of the process just described, and 

 the fact that, contrary to the view expressed by Pasteur, the 

 putrefaction occurring in the colon is not essential to digestion. 

 The above-named workers performed their experiments on a 

 patient suffering from a strangulated hernia at the junction of 

 the ileum and the caecum. This portion of the intestine was 

 removed by an operation, and the subsequent surgical treatment 

 necessitated the construction of an artificial evacuatory passage 

 (anus prceternaturaUs) at the extremity of the small intestine, until 

 complete union of the severed portions was restored, an affair of 

 six months' duration. Meanwhile, the contents of the intestine 

 were discharged through this artificial passage, and, though no 

 digestive functions were performed by the colon, the patient 

 nevertheless kept in good health, and even increased in weight. 

 This will explain why Nencki regarded the development of anti- 

 septic digestion as the goal of the physiology of nutrition, i.e. 

 digestion in which the putrefaction occurring in the colon is 



