44 



Scientific Proceedings (78). 



necrosis differing from previously described liver-necrosis. With 

 this necrosis there is associated a fibro-blastic proliferation giving 

 the picture of an early intralobular cirrhosis. 



27 (1205) 



The comparative effect of adrenalin on the pupil and blood pressure 

 in cats and rabbits. 



By T. S. Githens. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute.] 



Several years ago Meltzer showed that there was a striking 

 difference in the response of rabbits and cats to instillation of 

 adrenalin in the eye after excision of the superior cervical ganglion. 

 Whereas in rabbits full dilatation was obtained by a single instilla- 

 tion, in cats it was obtained inconstantly and only after very 

 numerous instillations. 



In order to determine whether this difference in behavior was 

 due to a difference in the susceptibility of the iris in the two 

 species to adrenalin, I gave this by intravenous injection and 

 made a quantitative study of the iris on both the normal and 

 gangliectomized sides. I found that contrary to expectation, 

 the iris of the cat was much more sensitive than that of the rabbit 

 both in the intact and gangliectomized eye. Whereas 0.1 mg. 

 per kilo, caused in the rabbit only slight dilatation of the normal 

 pupil, this dose caused maximal dilatation in the normal pupil 

 of the cat. On the gangliectomized side 0.01 mg. per kilo which 

 had very little effect in the rabbit, caused almost maximal dilata- 

 tion in the cat. 



It was noted however that the duration differed in the opposite 

 direction, being much greater in the rabbit. Thus a dose of 0.1 

 mg. per kilo, which caused dilatation lasting half an hour in the 

 gangliectomized cat's pupil, caused dilatation lasting more than 

 three hours in the rabbit. Smaller doses showed a similar relation. 



In order to determine whether this relationship is true of 

 smooth muscle in general or is limited to the iris, I studied the 

 rise of blood pressure in the two species. The results showed that 



