16 



Scientific Proceedings (69). 



temporary depression followed by recovery and sometimes stimu- 

 lation while the intestine was still in the solution of the salt. 

 Complete abolition of rhythmic contractions and decrease of 

 tonus were observed when much higher concentrations were used, 

 but the effect was not permanent in these experiments as recovery 

 in pure Locke solution took place after the intestine had been 

 suspended in N/500 nickel acetate for twelve minutes. The 

 reaction to pilocarpine and of barium was studied in experiments 

 with both of the metals. The evidence obtained points to injury 

 to nerve endings as well as of the muscle fiber, but the latter was 

 in some experiments much more resistant. 



12 (1076) 



A note on the failure of pituitrin to sensitize the sympathetic 



system. 



By R. G. Hoskins (by invitation). 



[From the Laboratory of Physiology of the Northwestern University 



Medical School.] 



In 1 91 2 Kepinow published the conclusion that the injection 

 of small quantities of pituitary extract "sensitizes" the point of 

 attack of epinephrin. 1 His observations were that a given dose 

 of epinephrin produced a greater mydriatic effect in rabbits and 

 cats, a greater vasoconstriction in the Loewi-Trendelenberg frog 

 preparation and a greater vasomotor effect in rabbits and dogs if 

 immediately before hand a minimal dose of pituitary preparation 

 had been injected. Kepinow's work has been quoted as the 

 basis for a rather far reaching conclusion that the pituitary gland 

 has normally the function of promoting the activity of the sympa- 

 thetic nervous system. 



In various researches on the vasomotor system we have had 

 occasion to use pituitary extract in connection with epinephrin 

 and nicotin and it became important to know to what extent 

 sympathetic sensitization occurs. As our previous work has been 

 done exclusively on dogs we have investigated the matter in this 



1 Kepinow, Archivfiir experimentelle Pathologie und Pharmakologie, 1912, LXVII, 



247. 



