915 
carpin, not on the small ones, the chance of augmenting the sensi- 
tivity by the aid of some substance or other, is much greater than 
at the terminal stage, when the gut has of itself reached its maximal 
sensitivity to pilocarpin for that day. 
In twenty cases we added serum (either serum alone or serum 
and piloearpin) to the gut, when it had obtained its constant sensi- 
tivity to pilocarpin. The serum and the pilocarpin was then removed 
by washing, after which the same dosis of pilocarpin that had 
previously yielded a constant result, was administered again. In 15 
out of these twenty cases the pilocarpin action was stronger after 
the serum than before (four times the reaction was much stronger, 
five times distinctly stronger and six times only slightly so). Once 
the action remained the same and four times the second dosis had 
less effect than the first. 
An instance of a considerable increase of the pilocarpin action 
through serum is shown in Fig. 1. 
Fig. 1. Influence of rabbit’s serum on the action of pilocarpin upon the 
urviving small intestine of the cat. 
a. 0,04 mgrms of pilocarpin yields a moderate contraction. 
b. OA ce. of rabbit's serum + 0,4 mgrms of pilocarpin yields a strong contraction- 
c. 0,04 mgrms of pilocarpin yields a stronger contraction than in a. 
