THE PANCREAS AND DIABETES G73 



tissue provides "a something," separate from the pancreatic juice, 

 (internal secretion of the pancreas), the lack of irhich is responsible for 



the sytn])toms of diabetes. 



Islet Theory: MorpholofjjiciiUy tlie ixincrcns may be reKiinlod a.s Htroma, 

 ducts, acini and islamls of LanRcrhans. It lias been proposed, notably by Opio" 

 in this country, tliat tho antidiabetic internal secretion of the; pancreas is elabo- 

 rated by islet cells. This view hnds support in the following facts: (1) In 

 diabetes melitus the islets arc frequently found in a state of hydropic or hyaline 

 degeneration, while the reniainiiifz; organ may appear normal.*' ' (2) Cancer, pan- 

 creatitis and the experimental injection of caustics into the ducts very frecjuently 

 spare the islets and fail to cause diabetes. (3) It is claimed tluit in pancreatic 

 grafts, such as described above, islet cells predominate, while acinus cells and 

 ducts disai)pear. 



Grafts of this kind consist of much connective tis.sue, generally more or less 

 infiltrated with round cells, and collections of epithelium. Concerning the latter, 

 remains of ducts and acini are usually present in some proportion, andihcre are 

 also epithelial cell masses regarded as islets on mor])hological grounds. Differ- 

 ences of opinion still exist as to the relative proportion of tlie ditTerent epithelial 

 elements. Lombroso,"" whose exhaustive monograph reviews tlie literatute to 

 1910, concludes that the internal function of the pancreas is not mono|)olized 'by 

 islet cells. Bensley^' developed intra-vital staining methods which, for the first 

 time, made possible the sure differentiation of islet cells from duct or acinus 

 epithelium without reference to form or arrangement, and appears to ha\e i)rovcd 

 that these cells are regenerated from duct epithelium. He also showed the great 

 normal variations in size and number of islets in different individuals (guinea- 

 pigs). His study explains certain of the discrepancies which occur in the litera- 

 ture, especially in the estimation of the quantity of islet tissue in j)ancreatic 

 rests, grafts, etc. AUen^- has reported that when proper sized fragments of 

 pancreas, in connection with the ducts, are left in situ, and the remainder of the 

 gland is removed, the subsequent development of severe diabetes maybe coincident 

 with disappearance of islet tissue while acinus cells and ducts are unaffected. 

 This operation, according to Allen, is eminently satisfactory for producing ex- 

 perimental diabetes without infection and without loss of the external secretions. 



The Nature of the Internal Secretion of the Pancreas. — 



Direct evidence on this subject i» lacking. Such a secretion has never 

 been isolated. Even the experiments made with the feeding of fresh 

 pancreas and with extracts of the gland have led to no solid advance. 

 Reports of improvements following the administration of any substance 

 in diabetes are worthless unless accompanied by proof of the constancy 

 of the diet, of the amount of work perfomed, and of other factors which 

 are known to influence the course of diabetes. Some glimmer of suc- 

 cess appeared to have attended the intravenous use of an extract made 

 by Zuelzer/^ although deleterious by effects occured, and the apparent 

 improvement could have been due wholly to retention. According 

 to Hedon and Drennan, amelioration of the severity of pancreas 

 diabetes as evidenced by a diminution of glycosuria has followed the 

 transfusion of blood from a healthy animal or the injection of fresh 

 defibrinated blood, and Forschbach, working with a parabiosis (or 



*8 "Diseases of the Pancreas," Lippincott & Co., 1910. 

 " See Homans. Jour. Med. Res., 1914 (30), 49. 

 soErgeb. der Phvsiol., 1910 (10), 1. 

 " Am. Jour, of Anat., 1911 (12), 297. 

 ^2 Glycosuria and Diabetes, Boston. 1913. 

 " Zeit. f. exp. Path., 1908-9 (5), 307. 

 43 



