494 SCIENCE PROGRESS. 



shows in his paper that the activity of the pancreas is 

 largely dependent on its blood supply — a temporary 

 anaemia of the gland induced by obstruction of the aorta 

 or by stimulation of the splanchnics causing a total sup- 

 pression of pancreatic activity, which may last several hours. 



The second paper on pancreatic innervation, by Mett, 

 deals chiefly with the influence of the vagus on the produc- 

 tion of the pancreatic ferments and especially of trypsin. 

 For the determination of the comparative proteolytic powers 

 of the various specimens of pancreatic juice, he employs a 

 new and simple method which presents considerable advan- 

 tages over the old carmine-fibrin method of Grutzner. 

 Capillary glass tubes of i mm. bore are filled with egg 

 albumen, which is then coagulated by insertion for five 

 minutes into water at 95° C. They are then cut by a special 

 machine into lengths of 1 cm. Two of these small tubes 

 are placed in each sample of fluid, whose proteolytic powers 

 it is desired to determine, and the whole is kept for seven 

 hours at 40° C. The amount of albumen remaining at the 

 end of the time is read off by means of a micrometer, and 

 the digestive powers expressed by the number of mm. 

 that have been digested. Thus, if the column of undigested 

 albumen was three mm. in length, the digestive power 

 of the fluid would be represented by seven. 



In the first place, Mett shows that the pancreatic juice 

 obtained by stimulating the vagus is active on all three 

 classes of food stuffs, and can therefore be regarded as 

 normal. It is an interesting fact that the pancreatic juice 

 obtained in this way from fasting animals is actively proteo- 

 lytic, whereas it is well known that a fresh extract of the same 

 glands would contain no trypsin. In the second place, in 

 cases where there is already a secretion of pancreatic juice 

 on stimulation of the vagus, we get, not only increased 

 secretion of fluid, but also increased formation of the fer- 

 ment, so that the juice obtained after stimulation of the 

 vagus is much more active than that obtained before. It is 

 evident then that the vagus contains, to use Heidenhain's 

 nomenclature, not only secretory but also trophic fibres to 

 the pancreas. 



