SECRETIN 37 



tact. From this fact the authors named conclude "it was 

 clear that the message from the isolated loop was carried by 

 way of the blood to the pancreas and that it must be some 

 new type of chemical substance which originated in the 

 intestinal mucous membrane under the influence of the acid. 

 In confirmation of this conclusion the mucous membrane of 

 the upper portion of the small intestine may be scraped off, 

 mixed with 0.4 per cent. HOI and the mixture filtered, when 

 it will be found that injection of this filtrate directly into the 

 circulation will induce a special flow of pancreatic fluid. To 

 this new substance produced under the influence of acid in 

 the intestinal cells we have applied the name ' secretin.' " 5 



The work of the authors quoted has been amply confirmed 

 in many quarters; and the chain of proof has been in a 

 sense completed by Wertheimer's discovery of secretin 

 in the blood of an isolated intestinal loop into which acid had 

 been introduced. The well considered and masterly studies 

 of Bayliss and Starling should be regarded as truly classical. 

 In this connection Swale Vincent 6 in a critical review of the 

 whole question of internal secretion regards the action of 

 secretin (after the glycogenetic function of the liver) as the 

 best-attested example of an "internal secretion" and in 

 strict sense more definitely established than the internal 

 secretions of the thyroid gland and the adrenal. And yet 

 the conditions of pancreatic secretion remain so confused 

 that the question of the role and significance of secretin is 

 in the author's opinion still far from final solution. 



In the first place it should be remembered that, as shown 

 by Wertheimer and Fleig, the flow of pancreatic secretion 

 may be induced by the introduction of acid into an intestinal 

 loop even if the blood of the loop is completely cut out from 



6 Literature upon Secretin : W. M. Bayliss and E. H. Starling, Ergebn. d. 

 Physiol., 5, 670-676, 1906; E. H. Starling, Lectures on Recent Advances in 

 the Physiology of Digestion, London, 1906; J. Pawlow, Nagel's H'andb. d. 

 Physiol., 2, 734-742, 1907; S. Rosenberg, ibid., 3', 141-146, 1910; C. Oppen- 

 heimer, Fermente, 3d ed., 193-194, 1910. 



8 Swale Vincent, Ergebn. d. Physiol., 9, 496-500, 1910. 



