Toxicity of Caffein in Nephrectomized Rabbits. 59 



is not less than in normal rabbits. In fact, it showed rather 

 a tendency to greater resistance after the kidneys had been re- 

 moved. Thus 100-150 milligrams of caffein per kilo failed to 

 produce symptoms in nephrectomized rabbits. As was shown by 

 the writers elsewhere, 1 15 omilligrams per kilo injected subcuta- 

 neously into normal rabbits are usually toxic. A dose of 200 mil- 

 ligrams per kilo proved fatal to one rabbit, but two others survived 

 with the manifestation of symptoms. It is interesting to recall 

 in this connection that similar results were obtained several years 

 ago by Meltzer and Salant 2 in experiments with strychnin in 

 nephrectomized rabbits. 



41 (650) 



A quantitative study of the pupil dilatation caused by adrenalin. 

 By DON R. JOSEPH. 



[From the Department of Physiology and Pharmacology of the 

 Rockefeller Institute for Medical Research.] 

 In the normal rabbit, adrenalin given subcutaneously has no 

 effect on the pupil; if given intravenously in fairly large doses 

 there may be a dilatation lasting less than a minute. S. J. Meltzer 

 and C. M. Auer have shown that after removal of a superior 

 cervical sympathetic ganglion in rabbits, the pupil of the corre- 

 sponding side dilates maximally upon the administration of 

 adrenalin either subcutaneously, intravenously or by instillation. 

 Their experiments were carried out from the qualitative point of 

 view, that is, fairly large doses of adrenalin were used and a 

 wide, long-lasting dilatation of the pupil on the gangliectomized 

 side resulted. 



I have recently made a quantitative study of the effects of 

 intravenous injections of adrenalin on the pupil after removal 

 of a superior cervical ganglion in rabbits. The object was to 

 determine the minimal dose that will give a dilatation, and also 

 the amount and duration of the dilatation produced by larger 

 doses. The doses of adrenalin used per kilo animal, expressed in 

 c.c. of the 1/1,000 commercial adrenalin solution, were 1/50, 1/30, 

 1/20, 1/10 and 2/10 c.c. 



1 Bull. 148, Bur. of Chemistry. 



2 Jour. Exp. Med., 1901, Vol. 5, p. 643. 



