48 PHYSIOLOGY AND TOXICOLOGY 



The only remaining autliority upon this portion of our subject, is Dr. Salisbur3\' 



A large female rattlesnake, without food for a year, died, and on dissection its 

 poison ducts supplied Dr. Salisbury with a small amount of venom. This was 

 used on plants, without having been tested upon animals. 



" About fifteen minutes after its removal, four young shoots of the lilac {Syringa 

 vulgark), a small horse-chestnut of one year's growth (CEsculus liippocastanum) , a 

 corn plant (^Zea mays), a sun-flower plant [Heliantlms annuus), and a wild cucumber 

 vine, were severally vaccinated with it. The vaccination was performed by dip- 

 ping the point of a penknife into the poisonous matter, and then inserting it into 

 the plant, just beneath the inner bark. No visible effect from the poison was 

 perceptible until about sixty hours after it had been inserted. At this time, the 

 leaves above the wound, in each case, began to wilt. The bark in the vicinity of 

 the incision exhibited scarcely a perceptible change ; in fact, it would have been 

 difficult to have found the points, had they not been marked when the poison was 

 inserted. 



" Ninety-six hours after the opei-ations, nearly all the leaf-blades in each of the 

 plants, above the wounded part, were wilted, and apparently quite dead. On the 

 fifth day, the petioles and bark above the incisions began to lose their freshness, and 

 on the sixth day they were considerably withered. On the tenth day, they began 

 to show slight signs of recovery. On the fifteenth, new but sickly-appearing leaves 

 began to show themselves on the lilacs, and the other plants began to show slight 

 signs of recovery in the same way. Neither of the plants was entirely deprived 

 of life." 



Dr. Salisbury afterwards comments upon the fact of the edges and apices of the 

 leaves being the parts first attacked. He also states that the leaves below the 

 points of innoculation were altogether unaffected, while those on the side upon 

 which the venom was inserted were the first to suffer. 



These experiments were made in June. 



An objection to the want of a precedent test experiment upon animals as to the 

 virulency of the poison used has been above suggested. This objection, it is true, 

 loses some weight in the presence of a positive result. I have mentioned it, how- 

 ever, because it was possible that the secretion of the snake in question might have 

 been altogether harmless, and the apparent results upon the plants only the effect 

 of a mechanical injury to their tissues. This very result occurred to me during 

 the summer of 1859. 



A large snake, nearly five feet long, was sent to me from Iowa. It came in a 

 very small, fiat box, and was so coiled that it must have been difficult for it to 

 move. When I removed it from its confinement it was sluggish, and was only 

 induced to bite upon being much irritated. During the month of July the snake 

 made no use of the bath in its cage; and, like the rest, took no food, nor did I feed it 

 as I did some of its companions. A week before its death, there is a record on my 

 notes of its having bitten a pigeon, which recovered in spite of a deep wound from 



' Influence of the Poison of the Northern Rattlesnake (Crotalus durissus) on Plants. By J. II. 

 Salisbury, M. D., N. Y. Journ. of Med., vol. xiii. New Series, 1854, p. 337. 



