104 



PHYSIOLOGY 



CHAP. 



survival of the islets, the internal secretion being served by the 

 islets only. 



Louibroso objected that the necessary counterproof was 

 wanting. It is not known whether complete extirpation of the 



pancreas (as far as possible) would 

 produce glycosuria in the rabbit. 

 It is known, indeed, that complete 

 ablation of the pancreas is not followed 

 by glycosuria in all animals. It is 

 absent in many granivorous birds 

 (pigeons), while it is seen in carnivora 

 (crows, falcons). Moreover, the effects 

 of total excision of an organ, and of 

 the slow and gradual suppression of 

 its function, may differ considerably. 

 Even in the dog, according to Hedon, 

 glycosuria may be absent or very slight 

 when a pancreas previously altered by 

 injection of paraffin into its ducts is 

 excised. 



After tying or cutting the ducts, 

 and after transplanting a segment of 

 the pancreas in the dog, numerous 

 observers (Hedon, Moruet, Laguesse, 

 Ssobolew, De Dorninicis, Hansemann, 

 Lombroso) found that conspicuous 

 groups of alveoli or of islets might 

 survive in perfect preservation, even 

 for a long time after the operation. 

 It was only in grafts upon animals 

 which had rapidly perished, that both 

 alveoli and islets were found to be 

 degenerated. On these data Lombroso 

 founded his theory that islets and 

 alveoli both co-operate in the internal 

 G.^ 33. section through the coats of secretion of the pancreas. 



Zuntz and Mayer extended the 

 period of observation with dogs thus 

 operated on to 440 days, and obtained 

 the same results as Lombroso. Visen- 

 tini, on the contrary, out of 24 dogs 



operated on by tying and cutting the two pancreatic ducts, found 

 in two of them (after 160 and 212 days, respectively, after the 

 operation) that the alveoli were not in the normal state, while the 

 islets, on the contrary, were well preserved. He omitted, however, 

 to notice the effect of excising the pancreas when thus altered, so 

 as to see how far it had been capable of functioning as an organ 



the stomach. Diagrammatic. (Mall.) 

 TO, mucous membrane ; e, epithelium ; 

 d, orifice of gland duct ; mm, muscu- 

 laris mucosae ; sm, submucous coat ; 

 cm, circular muscular layer ; Im, 

 longitudinal muscular layer; s, ser- 

 ous coat. 



