658 BUKRILL B. CROHN 



a lipolytic ferment (steapsin) which splits fats into fatty acids and 

 glycerin. 



It is thus seen that the acinar cells of the pancreatic parenchyma fur- 

 nish the three main ferments which are of the greatest physiological and 

 metabolic importance in the digestion of foodstuffs. 



Diseases that affect or originate in the pancreas interfere with its func- 

 tion in two ways. The disease process either blocks the excretory ducts of 

 the pancreas so as to prevent its important secretion from reaching the in- 

 testinal tract, or it acts by destroying the parenchyma of the gland proper. 

 The net result in either case is approximately the same, that is, the gland- 

 ular secretion that reaches the intestine is either markedly diminished or 

 completely absent. The natural inference is that the preparation and 

 digestion of the three main classes of foodstuffs is materially interfered 

 with or suspended, resulting in diminished absorption on the part of the 

 intestinal lacteals and epithelial cells, and a greatly increased excretion of 

 undigested food elements in the feces. In well defined and advanced 

 clinical cases such changes in absorption and excretion are often readily 

 demonstrated; unfortunately for the simplicity and comprehensibility of 

 the subject, it has been shown by numerous observers that such disturbances 

 are not bound to follow even the complete blockage of the duct system or the 

 destruction of by far a major portion of the secreting parenchyma of 

 the gland. A mass of evidence, experimentally produced or obtained 

 by careful clinical observation, has thrown much light on the subject and 

 clarified many points hitherto in dispute, yet has left some of the vital 

 points still unexplained and far from solution. 



Experimental Evidence of Disturbances in Metabolism, resulting 

 from damage to the parenchyma of the gland or to obstruction of its ex- 

 cretory duct system. The experimental work that antedated the middle 

 of the last century was in great part nullified by the lack of acquaintance 

 of the workers with the details of the anatomy of the duct system in the 

 animals operated upon (dogs). 



To Claude Bernard, in 1856, is credited the accomplishment of writ- 

 ing the introductory chapters to our knowledge of pancreatic lesions, ex- 

 perimentally produced. His earliest experiments consisted in injecting 

 into the duct system of the dog's pancreas irritating substances such as 

 bile and fatty acids, or blockage of the ducts by the injection of paraffin. 

 He was able to demonstrate a distinct disturbance in fat absorption and 

 metabolism; his animals developed fatty stools, showed increased ap- 

 petite but lost weight rapidly. The urine was not examined. The de- 

 struction of the pancreas in his animals was usually complete. 



Abelmann attempted to perform total pancreatectomy upon dogs. The 

 result observed was a complete failure on the part of the intestinal tract to 

 absorb fat; nitrogen absorption varied between 30 and 80 per cent; a 

 better absorption was demonstrable when the fat was administered in 



