INTESTINAL JUICE. 



sents the greatest difficulties in the investigation of its properties and uses. 

 If it be admissible to reason from the known mechanism of secretion in other 

 parts, it is fair to suppose that the normal secretion of the glands in the 

 mucous membrane of the small intestine can take place only under the 

 stimulus of food. The same cause excites the secretion of the pancreatic 

 juice and increases the flow of bile ; and the food, as it passes from the 

 stomach into the duodenum, is to a great extent disintegrated and is min- 

 gled with the secretions from both the mouth and the stomach. Under these 

 circumstances, it is evidently impossible to collect the intestinal juice under 

 perfectly physiological conditions, in a state of purity sufficient to admit of 

 extended experiments regarding its composition, properties, and action in 

 digestion. 



The experiments of Bidder and Schmidt, Thiry, Colin, Meade Smith and 

 others have given but little positive information with regard to the general prop- 

 erties, even, of the intestinal juice, to say nothing of its digestive action. It may 

 be stated in general terms, that the physiologists just mentioned have attempted 

 to obtain the pure secretion of the follicles of Lieberkiihn by isolating portions 

 of the intestine and either taking the secretion as it formed spontaneously or 

 exciting the action of the glands by various means. When it is remembered 

 how different the secretion of the stomach, under the natural stimulus of food, 

 is from the fluid produced during the intervals of digestion, it is evident that 

 little reliance is to be placed upon the experiments that have thus far been 

 made upon the lower animals. Nearly all observers agree, however, that the 

 intestinal juice which they have been able to collect is yellow, thin and 

 strongly alkaline. Some have found it thin and opalescent, while others 

 state that it is viscid and clear. According to Colin the closed follicles of the 

 intestine produce a viscid fluid, which probably exudes through their walls. 

 Colin came to this conclusion from observations upon a large, ribbon-shaped 

 agminate gland, about six feet (183 centimetres) in length, which exists in 

 the small intestine of the pig. In a case of fistula into the upper third of 

 the intestine in the human subject, produced by a penetrating wound of the 

 abdomen which will be referred to again Busch found a fluid that was 

 white or of a pale rose-color, rather viscid and always strongly alkaline. The 

 maximum proportion of solid matter which it contained was 7*4 and the 

 minimum, 3.87 per cent. The secretion apparently could not be obtained in 

 sufficient quantity for ultimate analysis. No better opportunity than this 

 has been presented for studying the intestinal juice in its pure state. The 

 nature of the case made it impossible that there should be any admixture of 

 food, pancreatic juice, bile or the secretion of the duodenal glands; and 

 during the process of digestion, the lower part of the intestine undoubtedly 

 produced a perfectly normal fluid. 



From what has been ascertained by experiments upon the lower animals 

 and observations on the human subject, the intestinal juice has been shown 

 to possess the following characters : 



Its quantity in any portion of the mucous membrane which can be ex- 

 amined is small ; but when the extent of the canal is considered, it is evident 



