408 INTERNAL SECRETIONS OF PANCREAS AND SPLEEN. 



containing arterial blood than it was in that containing venous 

 blood. 



"It can be seen that in these two experiments arterial 

 blood showed itself as inactive as venous blood. One cannot, 

 therefore, ascribe the unquestionable action of the extract of 

 congested spleen upon the pancreatic proferment to the oxy- 

 gen of splenic tissue." 



There is one feature in this connection, however, which 

 requires elucidation: the influence that the use of fasting dogs 

 might have had on the experiments. We have seen that under 

 these conditions suprarenal activity becomes reduced; the 

 blood may, therefore, contain but a minimum of oxidizing 

 substance. Herzen performed an experiment which not only 

 confirms our conclusion that zymogen and trypsinogen are not 

 identical bodies, but also shows that fasting does not influence 

 the results just given. As Herzen's experiment has already 

 been reviewed at length, we will only reproduce its salient 

 points. The pancreas of a fasting dog (hence rich in tryp- 

 sinogen and other ferment-forming agencies) was infused in 

 glycerin, and this in turn was mixed with eight samples of 

 blood (bled directly in double its quantity of glycerin), four 

 being taken from a fasting dog and four from a dog in full 

 digestion with its spleen greatly dilated. The four samples 

 were taken in both animals from the femoral artery, the 

 femoral vein, the splenic artery, and the splenic vein. Fibrin 

 was then added to each sample. "After 1 hour there was still 

 no trace of digestion under the influence of the femoral blood, 

 arterial or venous, nor of the splenic arterial blood of the 

 fasting dog; first traces of digestion were beginning to mani- 

 fest themselves under the influence of the splenic venous blood 

 of this animal. Digestion was rather advanced in the case of 

 the femoral arterial and venous blood and splenic arterial 

 blood of the digesting dog; the fibrin had almost entirely dis- 

 appeared under the influence of the splenic venous blood of 

 the same animal." This seems to us to confirm not only the 

 view held by Herzen, that the splenic ferment is the only 

 agency capable of converting trypsinogen into trypsin, but 

 also that trypsinogen does not, like zymogen, possess affinity 

 for oxygen. 



