402 INTERNAL SECRETIONS OP PANCREAS AND SPLEEN. 



But how, under these circumstances, can we account for 

 the experimental results reached by Schiff and Herzen, Heiden- 

 hain, Lepine, Pachon and Gachet, and Popelski? All these 

 observers in one way or another have unquestionably shown a 

 direct relationship between the blood-serum and trypsinogen, 

 Heidenhain and Popelski considering oxygen as the convert- 

 ing agency, with solid experimental data to sustain them; 

 Schiff, Herzen, and the other investigators mentioned attrib- 

 uting to the splenic ferment the same mission, with equally 

 strong experimental backing. How account, for example, for 

 the results observed in the following experiment of Herzen's? 

 Two fasting dogs, having received all the meat they could eat, 

 were at once submitted to ligation of the pylorus, bile-duct, 

 and jejunal end of the duodenum, and also, in one of the dogs, 

 of the hilum of the spleen. Albumin having been introduced 

 into the duodenum, both dogs were killed after seven hours. 

 In the dog with ligated splenic hilum the albumin was intact; 

 in that in which the splenic vessels were free, the albumin had 

 disappeared. This and other experiments to which we have 

 referred may, indeed, be said to prove whichever be the pre- 

 vailing converting agency that a communication between the 

 blood-channels and the ducts exists. 



We have seen that there is no evidence to show that the 

 acini in direct communication with the ducts also open into 

 the blood-vessels; these, as elsewhere, form a close net-work 

 around the acini, but they do not open into the blind pouches 

 of the latter. Could the communicating channels traverse the 

 islands of Langerhans? That these organs do not possess such 

 channels or even ducts has been shown by Dogiel, 25 who studied 

 this question in a well-preserved human pancreas treated by 

 the chrome-silver method, and in which the gland-ducts, "even 

 in their finest intra-alveolar branches, were well stained." Yet 

 these structures possess morphological characteristics that are 

 suggestive. Dogiel, for example, found that they possessed 

 relatively large capillaries located in the cellular trabeculae. 

 All investigators seem to agree upon the unusual size of those 

 vessels. Kiihne and Lea define the islands as "glomerular 



Dogiel: Bb'hm and von Davidoff, loc. cit. 



