596 SPECIAL PHYSIOLOGY. 



The bile and pancreatic juice must be speedily, and almost simultaneously, 

 mixed with the food. In the ostrich, however, these secretions are mixed with 

 the food at some distance apart, the bile escaping through the single hepatic 

 duct, close to the pylorus, and the pancreatic juice also by a single duct, 3 feet 

 lower down. 



In Reptiles, the pancreas is usually large. It is larger in the herbivorous 

 than in the carnivorous Saurians, being largest in the Iguanas. In the Che- 

 lonians, this gland is even ramified, as it is in the Rodents. In the Ophidians, 

 it is either long and bifid, pyramidal, or round. The duct is nearly always 

 single, and generally enters the duodenum separately, but sometimes with the 

 bile-duct. In the Serpents, the pancreas is joined to the spleen, and has even 

 been confounded with it. 



In the Amphibia, the pancreas is found in the mesentery, between the 

 stomach and duodenum ; it is smallest in the purely aquatic species, such as 

 the tritons. In the frog, the bile-duct perforates the pancreas, and, it is be- 

 lieved, receives small pancreatic ducts in its course. In the lowest Amphibia, 

 as in the siren, the pancreas is much subdivided, so as to approximate to the 

 form of the pyloric appendages in the Fishes ; its ducts are no longer united 

 into one, or into a few principal trunks, but form numerous parallel canals, 

 opening separately into the duodendum. 



In many Fishes, there are found, opening into the duodenum, near the 

 pylorus, certain simple tubular or ramified follicular prolongations of the coats 

 of the intestine, lined by a glandular membrane, named the pyloric appendages. 

 The food does not enter them, and, from their position and glandular charac- 

 ter, they have usually been regarded as the homologues of the pancreas, but 

 they are somewhat anomalous organs. In the sturgeon, these appendages are 

 so numerous as not to have been counted ; the cod and whiting have about 

 120, the salmon 60, averaging 6i inches in length, the sprat 9, the perch 3, the 

 turbot 2, and the ammodytes and polypterus only 1. They are entirely absent 

 in many Orders. When few in number, they open separately into the intes- 

 tine ; but when numerous, they combine into clusters, each opening by a single 

 orifice. Thus, 50 caeca, in the pilchard, open by 30, and in the tunny by only 

 5 orifices ; in the swordfish, there are only two openings, and, in the sturgeon, 

 the multitudinous caeca open by a single short duct. They are largest and 

 most numerous in fishes of active digestion and rapid growth, and, on the 

 whole, most developed in the more voracious tribes. They are more com- 

 monly few and large in the Osseous fishes, whilst in the Cartilaginous group 

 they are usually smaller and numerous. When absent, the mucous membrane 

 of the intestine below the pylorus is, sometimes, as in the eel, thick, vascular, 

 and glandular, and yields, on pressure, a copious secretion. 



The pyloric appendages are certainly glandular organs and not intestinal 

 diverticiila, intended for purposes of absorption ; but it has been suggested 

 that they are special glands, and that the true representative of the pancreas 

 in Fishes, is a small gland sometimes found attached to the liver. Such an 

 organ exists in the carp, pike, silurus, sturgeon, and ray, in which fish it is 

 large and has a duct opening near the bile-ducts, and in many other species. 

 In some instances, it would seem to be a detached portion of the liver, but in 

 other cases, its pancreatic structure is undeniable. Certain fish, as, for ex- 

 ample, the trout, possess this organ as well as the pyloric appendages ; in 

 others, it is very small ; in some, it is not found, but may then be represented 

 by glandular structures in the walls of the intestine. Bernard, who doubts 

 the pancreatic character of the pyloric appendages, asserting that their secre- 

 tion is acid and viscid, like the intestinal juice, and not alkaline and diffluent, 

 like the pancreatic juice, states that a watery emulsion of the proper pancreas 

 of the ray, converts starch into sugar, and decomposes fatty matters into their 

 proper fatty acids and glycerin, like the secretion or substance of the pancreas 

 of the higher V ertebrata. 



In certain Cephalopods, a laminated and folliculated sac, connected with the 

 two hepatic ducts, in other Cephalopods, a spiral appendage, and, in many 

 Branchio-gasteropods, as in apiysia and doris, a long ceecal glandular tube, 

 which communicates with the intestinal canal below the stomach, may rep- 

 resent a molluscan pancreas. 



In the Annulosa, the Insects and some others, have tubuli, connected with 



