662 BURRILL B. CROHN 



that one of the most successful means for producing experimentally pan- 

 creatic necrosis and degeneration, .as also creating fat necrosis, was 

 by this very method, namely, tying off of the ducts. Not only the ex- 

 clusion of the pancreatic secretion from the intestine is thus carried out, 

 but a veritable decomposition, hemorrhage and necrosis of the gland results 

 in a large percentage of cases. If the animal survives the procedure and 

 its resultant effects on the gland, the least after-effect is a chronic pro- 

 ductive obliterating pancreatitis or an atrophy of the gland. 



See the experiments of Hildebrand and of Dettmer in Part II of this 

 article, on the experimental production of fat necrosis in animals. 



Finally, we may bring into evidence the results obtained by McClure, 

 Vincent and Pratt. In a series of four dogs, they removed entirely the 

 processus lienalis and the corpus pancreatis and formed of the remaining 

 processus uncinatus a subcutaneous graft. In a fifth dog the processus 

 uncinatus was allowed to remain in the abdomen though completely cut 

 off from the intestinal wall. The mean average of fat absorption in the 

 four animals was 50.19 per cent, a figure which is considerably better than 

 that reported by Pratt, Lamson and Marks who caused an atrophy of the 

 gland by ablation of the ducts and the insertion of omentum between the 

 cut ends. Thus it would seem that the preservation of a viable graft helps 

 to maintain absorption metabolism. In dog 4 of the series of experiments 

 by McClure, Vincent and Pratt, the main duct of the processus uncinatus 

 was saved with the graft and brought out upon the surface of the body 

 so that abundant pancreatic juice was continually escaping and no utiliza- 

 tion of the external secretion was possible. Yet the dog absorbed 74.3 

 per cent of- the ingested fat. Upon muzzling the dog it was shown that 

 the amount of fat actually absorbed per kilo was sustained. In two 

 of the dogs in this series a more marked deficit was shown, absorption 

 amounting only to 27.37 per cent and 23.9 per cent. 



At a secondary operation, these authors removed the subcutaneous 

 pancreatic graft from the animals. Fat absorption subsequent to this total 

 pancreatectomy fell to between 17.59 per cent and 45.3 per cent, averaging 

 now only 31.8 per cent. It is remarked that this is not an inconsiderable 

 amount of fat for an animal completely lacking in pancreas to absorb. 



It is difficult to harmonize the various findings of the many investi- 

 gators who have undertaken to clarify this problem. On the other hand 

 it is difficult to escape from the following conclusions : 



1. Normally, the external secretion of the pancreas is an important 

 agency in the digestion and the absorption of fat and nitrogen. 



2. Exclusion of pancreatic juice from the intestine of dogs causes a 

 prompt, though moderate drop in absorption of food products. 



3. Total extirpation of all pancreatic tissue causes very severe loss in 

 absorption power (as well as diabetes), though some persistence of absorp- 

 tion of fat and nitrogen is seen. 



