52 THE WORK OF THE DIGESTIVE GLANDS 



out a double vagotomy.) Lastly and this is the most essential character- 

 istic of our experiments we employ in the sham feeding an immediate, 

 uniform, and perfectly adequate criterion. This is an important im- 

 provement as compared with the experiments of Schiff, 



The negative effect of sham feeding after the vagotomy does not 

 prove, however, that the gastric glands are deprived of all secreting 

 power. It only shows that certain exciting impulses, which reach 

 the gastric glands by way of the vagi, have been removed. It is 

 possible that other forms of stimuli exist, which act on the gastric 

 glands through other nerves, or even in some wholly different way, 

 entirely without nerves. In the act of eating, however, the gastric 

 glands receive their normal impulses to activity by means of nerve 

 fibres which run in the vagi. 



But what kind of fibres are these? Are they special secretory 

 fibres or do they only influence the glands indirectly for example, 

 through the medium of the vessels ? According to the view now 

 prevalent with regard to secretory phenomena in glands generally, the 

 second supposition is but little probable, and it becomes still less so 

 could we adduce direct proof in favour of the truth of the first. 

 The stimulating effect of the sham feeding experiment can easily 

 be graduated. We can, for instance, give a dog a highly appetising 

 food, or, on the other hand, offer it a meal but little relishing. It is 

 well known that a dog eats flesh with much greater greed than bread. 

 If we give it bread we obtain much less juice, and of a much more 

 watery kind ; that is to say, less rich in ferment. Likewise, when we 

 give pieces of flesh at long intervals, we obtain not only less juice than 

 if the dog had been fed rapidly, but the juice possesses a much lower 

 digestive power. It follows from this that the stronger we stimulate, 

 the more and the richer the juice we receive. This fact is, however, 

 the best proof of the specific activity of the nerve fibres supplying the 

 glands. If only vasomotor (dilating) fibres for the glands were con- 

 tained in the vagi nerves, an augmented flow of juice from strong 

 excitation would mean a lessening of the concentration. The more 

 rapidly the fluid passes through the glands, other things being equal, 

 the less specific constituents could it carry away in solution from them. 



In proof of the above I give here a few figures taken from the work 

 of Dr. Ketscher : 



DIGESTIVE POWEK OF THE JUICE. 



Pieces of flesh given at intervals. Pieces of flesli given continuously. 

 GJ nun. Si iiiDi. 



2 ) ...../,] 



^ 8 



5^ 7J 



