EXPERIMENTA L E VIDENCE. 5 5 7 



exudation and the simple juice. Pilocarpine, he found, did not cause 

 increased secretion, nor did electrical stimulation. He describes the 

 juice as consisting of a yellow fluid, in which are suspended flocculi, 

 staining deeply with eosin, and mainly mucous in nature. The alkalinity 

 is marked. Albumin and globulin are present, and what he regarded as 

 probably albumose. He also found a small amount of urea. The secre- 

 tion had no action upon proteids. From starch paste was formed after 

 twenty-four hours a fermentable sugar. This action was shown more 

 powerfully in the earlier than the later months after the operation. 

 Eaw starch was not affected. He found that dextrose (not maltose) was 

 formed both from starch and glycogen. No fat-splitting action was 

 manifest, but the juice easily emulsified fat. The loop experimented 

 upon was found to be situated about three times as far from the stomach 

 as from the large intestine. Pregl calculates that the whole intestine 

 would secrete nearly 3 litres in twenty -four hours. 



It is difficult to say to what extent we are justified, from experiments 

 performed on isolated loops, in forming conclusions regarding the nature of 

 normal succus entericus. The first question that suggests itself is, How far 

 is the fluid secreted a catarrhal production 1 As above stated, Pregl has 

 pointed out that the mere prolapse of the gut causes a catarrhal increase above 

 what he regards as the ordinary flow. The facility with which micro-organisms 

 could enter would tend to increase any pathological condition. The presence 

 of albumose in a fluid which does not digest proteid, and also of urea, suggests 

 a pathological condition. Many of the ferment powers attributed to the 

 juice might be due simply to desquamated epithelium from the walls of 

 the loop. 



Klecki l has criticised in the same way the experiments of L. Hermann, 

 Blitstein and Ehrenthal, and Voit, dwelling on the abnormal conditions of the 

 loop, and the small number of experiments upon which their conclusions are 

 based. He himself finds that when few micro-organisms are allowed to remain 

 in the gut, much less solid substance is finally found, and states that a large 

 amount of contents is found in Hermann's rings only when the intestinal wall 

 shows pathological changes, or if complete disinfection of the loop has not 

 been carried out. 



It would seem, therefore, that we must hesitate before accepting all the 

 conclusions that have been drawn from the employment of the methods of 

 isolated loops and Thiry-Vella fistulse, bearing in mind that the juice so 

 obtained is probably seldom entirely uninfluenced by the abnormal condition 

 induced by the operation. Many, however, regard it as probable that the 

 crypts of Lieberkiihn, through their lining epithelium, yield a secretion 

 which is of assistance in dissolving the products of digestion by other juices, 

 even if it has no very well-marked digestive properties itself. 



We may finally proceed to consider how far extracts made from 

 the intestinal wall are characterised by the possession of specific 

 properties. 



In the first place, we must bear in mind that the intestinal mucous 

 membrane has primarily, without doubt, an absorbing function. We 

 have also reason to believe that the digested food in its passage through 

 the epithelial cells may undergo considerable changes. Consequently, on 

 making extracts of these epithelial cells, we may be separating substances 

 which are never secreted into the lumen of the intestine, but which 

 merely exercise influence on the absorbed food as it passes through the 



1 Wien. Jclin. Wchnsclir., 1894, Bd. vii. 



