412 PHYSICAL AND CHEMICAL CHARACTERS OF INTES. JUICE. [BOOK II. 



SECT. 4. THE PHYSICAL AND CHEMICAL CHARACTERS OF THE 

 INTESTINAL JUICE. 



The intestinal juice is a pale yellow, usually somewhat turbid, 

 liquid, of powerfully alkaline reaction, possessing, according to Thiry, 

 a density of about 1010. 



It is precipitated by alcohol, by nitric acid, and by nitric acid and 

 heat, the precipitate being one of albumin. 



When treated with dilute acids, it effervesces, in consequence of 

 the considerable quantity of sodium carbonate which it contains. 



In the juice obtained by mechanical irritation, Thiry found from 

 2'2 to 2'8 per cent, of solid matters, from O f 7 to 1/2 per cent, of 

 albumin, and from 07 to 0'9 per cent, of ash, but the result is 

 certainly abnormal. Gumilewski in more recent and more reliable 

 researches on a dog with a Vella fistula situated 1*04 metre from the 

 pylorus and 0'48 m. from the caecum found the solid matters to 

 amount, on an average, to 1*50 per cent. ; these containing 0'43 per 

 cent, of Na 2 C0 3 and 6'49 per cent, of NaCl. 



From the researches of Gumilewski and Rohmann it would appear 

 that the alkalinity of in other words the amount of Na 2 C0 3 in the 

 intestinal juice is remarkably constant for the secretion of the same 

 fistula. 



The Enzymes of the Intestinal Juice. 



In investigating the enzymes of the small intestine three methods 

 of inquiry have been pursued : (1) the mucous membrane of recently 

 killed animals has been extracted with solvents, such as glycerin, 

 which have the property of dissolving enzymes, and the digestive 

 activity of the extracts has been determined in the case of the 

 various groups of alimentary constituents, (v. Wittich, Masloff): 

 (2) the intestinal mucous membrane has been carefully dried in the 

 air and portions of the dried mucous membrane have been digested 

 with the substances under investigation (Brown and Heron) ; this 

 method has only been applied to the investigation of the enzymes 

 which act upon carbohydrates, but has in the case of these yielded 

 results of the greatest interest and value : (3) the intestinal juice 

 has been collected and its activity determined by artificial digestions 

 carried on in the incubator : (4) the alimentary constituents, either 

 solid or in solution, have been introduced into a segment of intestinal 

 tube in animals with Thiry- or Vella-fistulse, and the products of 

 digestion have been examined. 



Action of the The earlier experimenters (Thiry, Leube 1 , Schiff 2 ) 

 intestinal juice asserted that the intestinal juice possessed proteolytic 

 on proteids. properties. Thiry limited this power to the digestion 



1 W. Leube, 'Beitrage zur Kenntniss des Diinndarmsaftes,' Habilitationsschrift, 

 Erlangen, 1868 ; ' Ueber Verdauungsproducte des Diinndarmsaftes,' Centralblatt f. d. 

 med. Wissensch. 1868, p. 289. 



2 Schiff, ' Nuove ricerche sul potere digerente del succo enterico,' II Morgagni, 1867, 

 No. 9. Abstracted in Centralblatt f. d. med. Wiss. 1868, p. 357. 



