412 Prof. Christison on the Poisonous Properties of Hemlock, 



Exp. VII. Two drops of conia were introduced under the skin of a strong frog 

 into the cellular tissue of the back. In three minutes there was obviously great general 

 weakness; and in four minutes such complete paralysis of the fore-legs, that even gal- 

 vanism applied to them excited no voluntary motion, but merely the usual twitches pro- 

 duced by that agent after death. In five minutesand a half the respiration ceased; in six 

 minutes there was no movement anywhere, except slight twitches of the hind-legs ; in 

 eight minutes the eyelids were insensible ; and after this no movement of any kind 

 could be induced, when the skin was pinched and pricked in various parts. In twen- 

 ty minutes the muscles of the hind legs did not contract when their nerves were gal- 

 vanized ; but they contracted briskly when a galvanic current was passed from the 

 nerve to the muscles. The heart continued to contract long after death. 



I believe there are few poisons which act on the frog with so 

 much energy as conia is here proved to do. 



Exp. VIII. The following experiment was tried on the effect of artificial inflation 

 of the lungs, the subject of experiment being a middle-sized dog, thin, and full- 

 grown. A tube was fixed in the wind-pipe, having a large elliptic lateral hole ; 

 and a brass syringe was fitted upon the extremity of the tube. By applying the 

 finger over the lateral hole, while the piston was gently thrust down, — then with- 

 drawing the finger, and allowing the injected air to rush out under the impulse of 

 the contracting chest, — next drawing up the piston, — and then re-applying the fin- 

 ger, it was found easy to maintain the respiration between fourteen and twenty-four 

 times per minute, which was the natural rate in this animal. Four drops of conia 

 were then introduced through a small aperture into the cellular tissue behind the 

 fore-shoulder. For fourteen minutes little effect was observed, possibly owing to the 

 animal being firmly tied, and also appearing to be of singularly dull sensibility from 

 the first. At this time three drops more were introduced into another wound ; but 

 at the very same instant, the animal made a few hurried inspirations and expirations, 

 followed by gradual diminution of the breathing, till it became diaphragmatic only, 

 and then, in seventeen minutes, nearly extinct. At this time the eyelids winked, 

 when the hand was brought rather suddenly near them ; and when the muzzle was 

 pricked, the muscles of the nose acted feebly, and the head was feebly withdrawn. 

 Artificial inflation of the lungs was immediately begun. The heart, which had 

 previously begun to beat slowly, very soon pulsated more firmly and quickly ; and 

 the usual convulsive twitches consequent on cessation of the breathing ceased. Af- 

 ter continuing the inflation for six minutes, and observing that the eyelids winked 

 when the hand was waved before the eyes, and that the head was very feebly with- 

 drawn when the muzzle was pricked, the process of inflation was discontinued for 

 one minute ; convulsive twitches of the limbs, chest, and abdomen immediately en- 

 sued, in consequence of which faint respiration was occasionally accomplished, but 

 nothing like regular breathing. These movements had nearly subsided, and the 

 heart had begun to beat more slowly, when the artificial inflation was resumed, and 



