THE QUANTITIES OF THE DIGESTIVE FLUIDS. 303 



into play ; but when we assume the concurrence of mechanical 

 and chemical movements, we do not take into consideration the 

 metamorphoses which the chyle undergoes in the vessels them- 

 selves before it reaches the subclavian vein. Still less would we 

 refer to the very hypothetical conversion of sugar into fat within 

 the villi ; but we might be led to conclude, from the striking 

 difference in the optical appearance of the cells described by 

 Weber, that, in addition to the mechanical absorption, certain 

 chemical alterations actually occur in the villi ; thus, for instance, 

 if we find in a certain portion of the intestine many strongly 

 refracting vesicles, we shall also find, somewhat higher up, where 

 the absorption is half completed, many others which are granular 

 and dark (appearing white in incident light), and some of which 

 are partially filled with a granular, and others with a lighter mass ; 

 and still higher up in the intestine we find only cells which are 

 filled with granular matter. No conclusions ought to be drawn 

 from these experiments of Weber, which we have only quoted for 

 the purpose of showing that, even in an anatomical point of 

 view, there is much to be done before we can hope successfully to 

 arrive at any explanation of the process of resorption. 



Bidder and Schmidt have at all events the merit of being the 

 first to determine directly the quantity of fluids which are poured 

 into the intestinal canal as digestive agents. The result of these 

 investigations very considerably exceeds all the assumptions which 

 had hitherto been made in reference to the amount of any of the 

 secretions ; who could have conceived, or ventured to assert, that 

 the juices which flow into the intestinal canal in the twenty-four 

 hours amount to almost the sixth part of the whole weight of the 

 body ? If we apply to the case of an adult man the quantitative 

 relations of the individual secretions obtained for animals accord- 

 ing to the above data, by Bidder and Schmidt, it follows from their 

 calculations, that a man whose weight is about 64 kilogrammes 

 [or about 10 stone] will secrete in the 24 hours, 



Saliva amounting to 1'6 kilogrammes, containing 15 grammes of solid matter. 

 Bile 1-6 n 80 



Gastric juice 6'4 192 



Pancreatic juice 0'2 20 



Intestinal juice 0'2 about 3 



The quantity of fluid which passes from the blood into the intes- 

 tine during the 24 hours is therefore far larger than the amount of 

 blood which, according to the most probable recent determiria- 



