74 PHYSIOLOGY OF ALIMENTATION. 



protein, mucin, urea, and the ordinary salts found every- 

 where in the secretions and tissues of the body. The amount 

 of carbonate is particularly high, to which fact the alkaline 

 reaction of the juice is attributed. 



The descriptions given of the secretion of the small in- 

 testine in the human being are practically the same as those 

 given above for the juice obtained from dogs. The best 

 observations on human intestinal juice are those of TUBBY 

 and MANNING, 1 HAMBURGER and HEKMA, 2 and NAGANO^ In 

 TUBBY and MANNING'S case pure intestinal juice was obtained 

 from a piece of intestine 3J inches long situated some 8 inches 

 above the ileocacal valve. Their description of the juice 

 is similar to that of other observers and may be taken as a 

 type. The daily yield of juice from this piece of intestine 

 varied from 19 to 35 c.c.; the specific gravity from 1.0016 

 to 1.0162, on the average 1.0069. The fluid was opalescent, 

 and on standing a sediment consisting of leucocytes and 

 desquamated intestinal epithelium formed. The juice gave 

 a strong alkaline reaction, and contained protein, mucin, 

 and the ordinary salts, of which the carbonates and chlo- 

 rides of sodium and potassium were the more conspicuous. 



Within the last few years our conceptions of the nature 

 of the chemical substances contained in the secretions of 

 the intestine and in the walls of this portion of the alimentary 

 tract have undergone great revision, and from having looked 

 upon this chapter of alimentation as comparatively unim- 

 portant we now rank it with chapters on the pancreas and 

 stomach. This is due to the discovery in the intestinal 

 juice and in the walls of the intestine of a number of new 

 chemical substances, an understanding of the functions of 

 which, together with a proper appreciation of the physio- 



1 TUBBY and MANNING: Guy's Hospital Reports, London, 1891, 

 XLVI1I. p. 277. 



HAMBURGER and HEKMA; Journal de Physiol., IV. p, 805. 



'NAGANO: Mittheilungen aus den Grenzgebieten der Medicin und 

 Chirurgie, IX, p. 393. 



