FERMENTATION PROCESSES IN THE INTESTINE. 371 



Fate Of the Ferments. With regard to the digestive ferments, Langley is 

 of opinion that they are destroyed in the intestinal canal ; the diastatic ferment 

 of saliva is destroyed by the HC1 of the gastric juice; pepsin and rennet are acted 

 upon by the alkaline salts of the pancreatic and intestinal juices, and by trypsin ; 

 while the diastatic and peptic ferments of the pancreas disappear under the 

 influence of the acid fermentation in the large intestine. 



The action Of the Nervous System on the secretion of the intestinal juice is 

 not well determined. Section or stimulation of the vagi has no apparent effect; 

 while extirpation of the large sympathetic abdominal ganglia causes the intestinal 

 canal to be filled with a watery fluid, and gives rise to diarrhoea (Budge). This 

 may be explained by the paralysis of the vaso-motor nerves, and also by the 

 section of large lymphatic vessels during the operation, whereby absorption is 

 interfered with and transudation is favoured. 



Moreau' S Experiment. A similar result is caused by extirpation of the nerves 

 which accompany the blood-vessels going to a loop of intestine (Moreau). [Moreau 

 placed four ligatures on a loop of intestine at equal distances from each otheri 

 The ligatures were tied so that three loops of intestine were shut off. The nerves 

 to the middle loop were divided, and the intestine was replaced in the abdominal 

 cavity. After a time, a very small amount of secretion, or none at all, was found 

 in two of the ligatured compartments of the gut i.e., in those with the nerves 

 and blood-vessels intact but the compartment whose nerves had been divided 

 contained a watery secretion.] 



The secretion of the intestinal and gastric juices is diminished in man in certain 

 nervous affections (hysteria, hypochondriasis, and various cerebral diseases) ; while 

 in other conditions, these secretions are increased. 



If an isolated intestinal fistula be made, and various drugs administered, 

 experiment shows that the mucous membrane excretes iodine, bromine, lithium, 

 sulphocyanides, but not potassium ferrocyanide, arsenious or boracic acid 

 (Quincke), or iron salts (Glaevecke). 



In sucklings, not unfrequently a large amount of acid is formed when the fungi 

 in the intestine (Leube) split up milk-sugar or grape-sugar into lactic acid. Starch 

 changed into grape-sugar may undergo the same abnormal process ; hence, infants 

 ought not to be fed with starchy food. 



184. Fermentation Processes in the Intestine. 



Those processes, which are to be regarded as fermentations or putre- 

 factive processes, are quite different from those caused by the action of 

 distinct ferments (Frerichs, Hoppe-Seyler). The putrefactive changes 

 are connected with the presence of lower organisms, so-called fermenta- 

 tion or putrefaction producers (Nencki) ; and they may develop in 

 suitable media outside the body. The lower organisms which cause 

 the intestinal fermentation are swallowed with the food and the drink, 

 and also with the saliva. When they are introduced, fermentation and 

 putrefaction begin, and gases are evolved. 



Intestinal Gases. During the whole of the foetal period until birth, 

 this fermentation cannot occur ; hence, gases are never present in the 

 intestine of the newly-born (Breslau). The first air-bubbles pass into 

 the intestine with the saliva which is swallowed, even before food 

 has been taken. The germs of organisms are thus introduced into the 



