98 



PANCREAS. 



pancreatic secretion is the first poured into 

 the intestines, and the cystic bile the last : 

 and always when there are three pancreatic 

 ducts, the secretion reaches the intestine early 

 by one of them, and the others have their 

 upenings close to the bile ducts, either before 

 or between them. It is not safe, however, to 

 draw any physiological conclusions from these 

 relative positions, even supposing them to be 

 constant ; for the ducts are so close to one 

 another, that the mixture of the fluids must 

 take place immediately, and their action on 

 the food be simultaneous. In one instance, 

 however, this is not the case ; in the ostrich 

 the bile duct opens close to the pylorus, while 

 the pancreatic is three feet removed from it; 

 this is the greatest separation of the two ducts 

 of any with which I am acquainted in the 

 animal kingdom. It would present, if ostriches 

 were commoner birds, great facilities for ex- 

 periment, and implies an action in both the 

 secretions entirely independent and auto- 

 cratic. 



Mammalia. The chief differences between 

 the pancreas in other mammalia and man re- 

 late merely to its colour, its consistence, its 



more or less marked division into lobes, its 

 form, its volume, its union into a single mass, 

 or its separation into two distinct parts, lastly, 

 its position and relations with different por- 

 tions of the peritoneum. Its form is generally 

 more or less that of a narrow band, divisible 

 into two portions ; one, the duodenal, following 

 the curvature of the duodenum, and placed 

 vertically or obliquely ; the other, gastro- 

 splcnic, extending transversely, and therefore 

 opposite the other, from the duodenum to the 

 spleen, against which it always abuts; the latter 

 is always developed, the former is often incon- 

 siderable or suppressed, and must be con- 

 sidered merely as an accessory portion. The 

 various forms and arrangements of the pancreas 

 do not appear to have anything to do with its 

 essential structure or function, or the parti- 

 cular exigencies of the animal ; they seem to 

 depend entirely on the relations of the neigh- 

 bouring organs, the presence or absence of an 

 abundant mesentery, the free movement of the 

 duodenum, &c., and to be influenced by con- 

 siderations of package. 



In the Onrang the form very much resem- 

 bles that of man ; in most other Quadruniana 



Fig. 74. 



Pancreas o/"f/<e Hat (natural size), shown hi/ tfirnivint) tip the duodenum, together with its proper mesentery, 

 and I lie free process of peritoneum extending thence to the left, in which the gland ramifies. Its arborescent 

 form and great extent are well sJioivn. 



