740 



THE ENDOCRINE ORGANS, OR DUCTLESS GLANDS 



to a muscle lever, so thai the regular rhythmic contractions can be regis- 

 tered on a drum (Fig. 190). 



Epinephrine inhibits the contractions of the intosline but stimulates 

 those of the uterus of most animals, the intestine preparation being the 

 more sensitive (Pig. 191). Indeed, it is said that the inhibition in this 

 case may be obtained with a solution containing 1 part of epinephrine in 

 20.000,000 of solution. In using this method, however, great care and 

 judgment must be exercised in drawing conclusions, because other sub- 

 stances present in the blood are liable to affect the contractions; thus, 



Air. vent 



Fig. 190. — Arrangement of apparatus for recording contractions of a uterine strip, intestinal 



strip, or ring, etc. The metal water-bath is made of a cheap metal water-pail with a heating rod 



soldered through the side at the bottom. A short metal tube is soldered into a 1-inch opening in 



the bottom to receive a perforated cork for connecting with the Harvard muscle-warmer inside. 

 (From Jackson.) 



certain substances in blood serum which have been produced by the act 

 of blood clotting may cause augmentation of the beat in both the intes- 

 tinal and the uterine preparations. A certain amount of epinephrine in 

 Locke's solution is consequently more likely to cause inhibition of the 

 intestine than a similar amount added to blood serum, because in the lat- 

 ter case the pressor substance will neutralize the depressor effect of the 

 epinephrine. On the uterine preparation, both the blood serum and the 

 epinephrine have pressor effects. As has been pointed out by G. N 

 Stewart, 68 if both preparations are employed for testing a solution sup- 



