CHAP. III.] PHENOMENA OF THE PANCREATIC SECRETION. 195 



impossibility -^ nas been already said that almost invariably two 

 to obtain ail pancreatic ducts exist. In the dog, the animal which, 

 the pancreatic with rare exceptions 1 , has been employed for experi- 

 juice secreted. m ents on the pancreatic juice, this is the case. The 

 larger duct alone can, however, be found in the living animal, and 

 therefore only a part of the pancreatic juice is obtained, the rest 

 always making its way into the duodenum by the accessory duct. 



Difficulty in The difficulties in obtaining a continuous flow of 



obtaining a normal pancreatic juice are extremely great. Usually 

 continuous the juice obtained a few hours, or for a day or two, 

 normal flow. after the operation possesses the characters which will 

 be referred to hereafter as normal, but very soon, probably as a 

 result of inflammatory changes affecting the gland, the secretion 

 loses its normal characters ; it increases in quantity, the percentage 

 of solids diminishing. It often, however, diminishes remarkably in 

 quantity, in consequence, doubtless, of the enlargement of the ac- 

 >ry duct. In the large majority of cases, the cannula soon 

 >ps out and, in a very few days, the continuity of the ligatured duct 



icomes re-established. 



GENERAL PHENOMENA OF THE PANCREATIC SECRETION. 



The general phenomena of the secretion of pancreatic juice have 

 jen discovered by observing, firstly and chiefly, animals in which 

 miporary fistulas have been established, during the time which elapses 

 jfore the functions of the gland become, as a result of the operation, 

 averted ; and secondly, animals in which permanent fistulaB have 

 m successfully established; as a rule, for reasons stated already, 

 le fluid obtained from permanent fistulse soon ceases to be normal. 

 So long as the condition is perfectly normal, the following is the 

 ler of events : 



After a fast lasting 24 hours or more, the pancreas ceases to secrete, 

 imediately after food has been taken, secretion commences, and the 

 rate of secretion increases rapidly, reaching a maximum some time 

 within the first three hours. The secretion then diminishes until 

 a period which Heidenhain states as extending from the fifth to the 

 seventh hour, when a rise occurs, which lasts to 9th llth hours. 

 The secretion then gradually sinks, until it absolutely ceases ; at 

 the 17th hour there is a very scanty secretion; at the 24th hour 



1 Colin of Alfort succeeded in establishing fistuloe in large ruminants, and thus 

 obtained larger quantities of pancreatic juice than any other observer (200270 

 grms. per hour in the ox). See 'Experiences sur la s6cr6tion pancreatique des grands 

 ruminants,' in the Comptes Rendus, Vol. xxxii. (1851), and his illustrated descriptions 

 in his Traits de Physiologic compares des Animaux Domestiques, Paris, 1854, Vol. i. 

 p. 631 et seq. Colin (1'Institut, 1851, p. 91, quoted by Bonders in his Physiologic des 

 Mcnschen, Vol. i., p. 260) and Frerichs (see 'Verdauung' in Wagner's Handworterbuch), 

 introduced cannulae into the pancreatic duct of donkeys. 



132 



