98 THE WORK OF THE DIGESTIVE GLANDS. 



(Dr. Lobaasoff). A solution of Liebig's Extract of Meat, judging from 

 the quantity of juice secreted, is a stimulus of only moderate strength. 

 The reason of this may possibly lie in the fact that the solution quits 

 the stomach, whose surface it should specifically excite, too quickly. If 

 so, it was to be expected that, if the ingredients of the meat extract 

 could be somewhat longer retained in the stomach, a larger quantity of 

 juice would be secreted. As a matter of fact, when we made a mixture 

 of meat extract with starch solution, and divided the cooled jelly into 

 pieces which were afterwards inserted into the stomach, we obtained, 

 as was anticipated, twice as much juice as would be yielded by the 

 same quantity of meat extract in simple watery solution. 

 Here are the figures from one of the experiments : 



Hour. Quantity of juice. Digestive power. 



1st ... 2-8 c.c. ... 5-0 mm. 



2nd . . . 2-2 ... fvO 



3rd . . . 2-8 ... 6-25 



4th ... 1-8 ... 5-88 



nth . . . 1-2 ... G-25 



C.th . . . 0-6 



7th . . . 0-7 ... J-G-5 



8th 0-2 , 



Total . . . 12-3 



This experiment is also interesting because it materially supports 

 the assumption which w r e have tacitly made, that all the substances 

 hitherto employed excite the nervous machinery by a reflex stimulus 

 from the mucous membrane, and not that they are absorbed into the 

 blood, and then act directly on the peripheral neuro-glandular apparatus, 

 or even on the glands themselves. It is at once apparent that, if the 

 meat extract acted through the blood, it would be much more effective 

 in solution than when mixed with starch- jelly, and, therefore, in a less 

 absorbable form. 



Particular care was also devoted to the investigation of vegetable 

 and animal fats. They were tested not alone on a dog with isolated 

 miniature stomach, but also on animals with gastric and oesophageal 

 fistula?, and finally on dogs which had survived the operation of section 

 of the vagi in the neck performed several months previously. In all 

 these cases the fat was directly introduced into the stomach without 

 swallowing. The result was invariably negative. 



Hence, when separately investigated, the majority of food-stuffs 

 showed an absence of stimulating effect upon the secretion of gastric 

 juice. To the minority which yielded a positive result, water and 

 certain as yet unknown constituents of flesh belong. 



