EXPERIMENTS OF HORSEFIELD. 909 



that on applying narcotics to the spinal marrow 

 and nerves of frogs, no twitching of the muscles 

 was excited, unless the poisons entered the cir- 

 culation ; yet he thinks their local action on the 

 nervous system is proved by the influence of 

 belladonna in dilating the pupil of the eye, and 

 of lead in causing paralysis of the hands. (Ele- 

 ments of Physiology, pp. 238242 628.) 



That poisons operate on the nervous system 

 through the blood, might naturally be inferred 

 from the fact, that their effects are produced 

 more rapidly on birds than mammalia, and very 

 slowly on cold blooded animals, or whenever the 

 circulation is languid, as in cases of nearly 

 suspended animation from cold, or by inhaling 

 carbonic acid. For example, it was long ago 

 observed by Dr. Horsefield, that when fowls were 

 wounded by arrows dipped in the chettik of Java, 

 they died in one minute; and that much de- 

 pends on the size of the animal ; for when large, 

 the poison is more diluted than when it is small : 

 that the poison of the upas killed a mouse in ten 

 minutes, a cat in fifteen minutes, a dog in one 

 hour, and a buffalo in two hours ten minutes.* 

 Similar results were obtained by Brodie, who 

 also found that the narcotic poisons operated 

 sooner on the brain, and thus arrested respiration, 



* It was also found by Thenard, that the respiration of air 

 containing, 1T Vg- its volume of sulphuretted hydrogen destroyed 

 the life of birds, T that of dogs, and ^ that of the horse. 



