EXPERIMENTAL EVIDENCE. 557 
exudation and the simple juice. Pilocarpine, he found, did not cause 
increased secretion, nor did electrical stimulation. Be describes the 
juice as consisting of a yellow fluid, in which arc 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. 
Raw 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 ? 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 clue 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 fistula?, 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 Lieberkuhn, 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 If'icn. Tdvti. JVchnschr., 1894, Bd. vii. 
