THE PANCREAS AS AN ENDOCRIN GLAND 711 



times the normal bulk. The authors explain this as a compensatory hyper- 

 trophy of the islets of the fetal pancreas to secrete more glycolytic fer- 

 ment in order to preserve a normal giycemia of the fetus. They con- 

 sider this an important proof of the regulating function of the islets 

 with reference to the blood-sugar. 



The results of the pathologic study of the changes in the pancreas re- 

 sulting from animal experimentation are just as widely divergent as the 

 autopsy findings in human diabetes. Ssobolew, Schultze, Sauerbeck, 

 MacCallum, Kirkbride, etc., have reported preservation of the islets with 

 atrophy and fibrosis of the acinar portion after ligation of the pancreatic 

 ducts. Minkowski found that ligation of the duct in guinea-pigs caused 

 a general fibrosis of both acini and islets. Pratt reported a similar de- 

 struction of both islands and ducts, and further affirms that all of the 

 islands may disappear without the production of diabetes. Milne and 

 Peters found that both islets and acini disappeared after ligation of the 

 duct in rabbits and cats. In dogs they found that a very small portion 

 of the gland left behind is sufficient to prevent diabetes ; this portion be- 

 comes hypertrophic with very large acini, and in many cases the islets dis- 

 appeared. Allen also saw some cases in which no islands were found, but 

 in the majority of his cases the islands were intact. 



The apparent contradictions regarding the significance of the patho- 

 logic conditions are undoubtedly due in part to a lack of a definite stand- 

 ard among pathologists and workers as to what is normal for the pan- 

 creas. Much of the trouble comes from different interpretations of the 

 same histologic picture. Particularly is this the case with regard to the 

 supposed transition forms between acini and islands, the regeneration 

 of new islands, island hypertrophy, etc. The question of the new forma- 

 tion of islets is particularly difficult. The writer is convinced that the 

 majority if not all of the formations interpreted as new islets are only 

 regeneration forms of acini arising from duct proliferations. The whole 

 question of the anatomic and functional independence of the islets is still 

 unsettled. Many writers have regarded them as only functional stages 

 of the acinar tissue. Dale, Vincent and Thompson believe that a new 

 formation of islands from acinar tissue can be produced by injections of 

 secretin. Bensley by means of vital staining and microchemical methods 

 could not confirm this, but believes that the islands have staining proper- 

 ties quite distinct from those of the acini, an argument for their anatomic 

 and functional independence. Homans confirmed Bensley as to the non- 

 formation of islands under the prolonged stimulation with secretin and 

 that the islands contain specific granules which allow of their positive 

 identification. Hb holds that there is no evidence of the conversion of* 

 acinous tissue into islets or the reverse. On the other hand, Oertel be- 

 lieves that the normal histologic picture of the pancreas is a very variable 

 one because of normal processes of progression and retrogression nor- 



