Scientific Proceedings. 



(207) 37 



mg. of nicotin, was injected daily into the ear-vein of the rabbits. 

 About ten seconds after such an injection the animal is seized with 

 a typical convulsion lasting from three to five minutes, after which 

 it is apparently entirely well until the next injection, when the 

 same thing recurs. This maybe repeated with great regularity and 

 without any exception every day and no tolerance to the poison 

 seems to develop. In two animals it was attempted gradually to 

 increase the daily dose to y 2 c.c. This, however, proved too 

 dangerous and was abandoned. All animals thereafter received 

 the same daily dose of ^ c.c, which was never increased or dimin- 

 ished. A number of animals died before they had received a 

 sufficiently large number of injections to cause any definite lesion. 

 Death ensued in some instances from some cause not at all refer- 

 able to the nicotin poisoning, but in others from numerous small 

 infarctions in the lungs, possibly caused by the intravenous injec- 

 tions. Cerebral hemorrhages, which are found so often in rabbits 

 treated with adrenalin injections, were never found in these animals. 



In animals which outlived a certain number of injections, various 

 distinct and characteristic lesions were found. It seems, however, 

 that not all animals are equally susceptible. What has been 

 observed in the numerous experiments with adrenalin seems to be 

 true also for nicotin. Now and then, how frequently the authors 

 were not able to say, rabbits are found that will respond to 

 the daily nicotin injection with the typical convulsion, but after 

 months of this treatment fail to show any of the characteristic 

 lesions about to be described. These lesions seem to be identical 

 in every respect with those found after intravenous injections of 

 adrenalin. After 18 injections slight changes are apparent in the 

 bulb and arch of the aorta. After 38 injections very marked and 

 characteristic macroscopic and microscopic lesions can be recog- 

 nized. Aneurysmatic dilations of the aorta are very distinctly 

 visible. There may be either a single aneurysm, or, what is more 

 frequent, several in various parts of the vessel. 



These dilations, as a rule, do not involve the entire circumfer- 

 ence of the vessel, but only a limited portion of it, thus presenting 

 the appearance of aneurysmatic pouches. On the interior surface 

 of the aneurysmatic dilations and their immediate neighborhood, 

 larger and smaller patches of calcification of varying shapes are 



