378 INTERNAL SECRETIONS OF PANCREAS AND SPLEEN. 



was infused in pure glycerin and the infusion was divided into 

 eight equal portions. These eight portions were mixed with 

 eight samples of blood received directly into a double volume 

 of glycerin, of which four came from a fasting dog and four 

 from a dog in full digestion with the spleen greatly dilated. 

 The four samples were taken in both animals from (1) the 

 femoral artery, (2) the femoral vein, (3) the splenic artery, 

 and (4) a large splenic vein. The eight portions were then 

 given the usual dose of fibrin and placed at a temperature of 

 40 C. Now, it is evident that the femoral and splenic arte- 

 rial blood of the two animals contained more oxygen than 

 their venous blood; the former, then, according to Heidenhain, 

 should exercise a powerful influence on the digestion, equal 

 in the two dogs. On the other hand, according to Herzen, the 

 splenic venous blood alone should exercise this influence and 

 especially that of the digesting animal. The result of the 

 experiment was as follows: After one 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 fast- 

 ing dog; first traces of digestion were beginning to manifest 

 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 disappeared 

 under the influence of the splenic venous blood of the same 

 animal. 



"The answer could not be clearer: the product of the 

 internal secretion of the spleen, borne therefrom by the cir- 

 culating blood, is present during the period of the dilation 

 of the spleen in feeble, but appreciable, quantity in the blood 

 of the general circulation and abundantly in the splenic venous 

 blood. The venous blood returning from the contracted spleen 

 only contains it in very small quantities. This experiment, 

 several times repeated, always gave the same result, showing 

 that it is not the blood as such which favors the transforma- 

 tion of pancreatic zymogen into trypsin, but that, by picking 

 up from the spleen the unknown substance possessing this 

 property, the blood becomes its vehicle and means of commu- 

 nication with the pancreas. 



