392 Prof. Christison on the Poisonous Properties of Hemlock, 



poisoning ; but this is not an essential phenomenon. The mus- 

 cular contractility of parts directly acted on, — as when a volun- 

 tary muscle, a loop of intestine, or the heart, is brushed over 

 with conia or its muriate, — is sometimes impaired, sometimes al- 

 most immediately annihilated. But this effect, as will be evi- 

 dent from the details of the experiments, is not invariable. Un- 

 der the remote or indirect action of the poison, the muscular 

 contractility remains altogether unaffected : when an animal is 

 killed with the poison applied to the eye, a wound, or the like, 

 both the voluntary and involuntary muscles contract for a long 

 time after death, when stimulated, either directly or through the 

 medium of their nerves, by mechanical irritation or by galvanism. 

 The blood undergoes no apparent alteration, except those inci- 

 dental to death by asphyxia; it coagulates firmly after death, 

 if immediately withdrawn from the bloodvessels. The heart, 

 contrary to Geiger's statement, remains wholly unaffected, — 

 contracting vigorously for a long time after all motion and respi- 

 ration and other signs of life are extinct, — and containing after 

 death, not florid, but dark blood in its left cavities. The exter- 

 nal senses continue little, if at all, impaired, till the breathing 

 is nearly arrested ; and volition is also retained. The action of 

 conia, in short, is exerted chiefly on the spinal chord. In its na- 

 ture that action is the counterpart of the action of nux-vomica 

 and its alkaloid strychnia. Strychnia irritates the spinal chord, 

 producing violent, permanent spasm of the muscles, and death 

 by asphyxia from spasmodic fixing of the chest. Conia, on the 

 contrary, exhausts the nervous energy of the spinal chord, pro- 

 ducing general muscular paralysis, and asphyxia from relaxation. 

 Few poisons equal conia in subtilty or swiftness. A single 

 drop put into the eye of a rabbit killed it in nine minutes ; three 

 drops used in the same way killed a strong cat in a minute and 

 a-half ; five drops poured into the throat of a small dog began to 

 act in thirty seconds, and in as many seconds more motion and 

 respiration had entirely ceased. But the most extraordinary evi- 



