BOTANY. 327 



air disengaged is almost wholly pure oxygen. The total volume of 

 the nitrogen disengaged is much more considerable than the volume 

 of the plant ; and, on submitting this plant to elementary analysis, it 

 is found that, for equal weights, it contains much less nitrogen than a 

 portion of the same plant not subjected to the experiment. The facts 

 show that, in the act of growth, in submerged plants, nitrogen proceeds 

 from the decomposition of the elements themselves of the plants ; that 

 consequently are-supply is necessary, and, consequently, nitrogen, free 

 or combined, is essential to the life of the plant. In the experiments 

 instituted by Cloe's and Gratiolet, a ten thousandth of ammoniacal 

 salts dissolved in water always proves injurious. The decomposition 

 of carbonic acid diminished and ceased after some hours ; whence the 

 conclusion that the plant assimilates directly nitrogen in solution in 

 water. They have also found that whatever may be the position of the 

 leaves of Potaniogeton in water, carbonate of lime is decomposed by 

 the superior surface of the leaves, and never by the inferior. They 

 have also ascertained that the oxygen produced by the decomposition 

 of the carbonic acid has a definite course ; that it descends inva- 

 riably from the leaves towards the roots. Thus, when the stem is 

 placed horizontally in water, the emission of gas always takes place 

 nearest the root of the plant. Institut. 



INFLUENCE OF THE POISON OF THE RATTLESNAKE ON PLANTS. 



THE following facts were communicated to the American Association, 

 Albany, by Mr. J. H. Salisbury. In June, 1851, a large female rat- 

 tlesnake, which had been caged in the New York State Cabinet of Nat- 

 ural History, died. On dissection, its stomach and intestinal canal were 

 found entirely empty, as much so as if they had been scoured out with 

 soap suds. The sack in which the poison is emptied was laid open, 

 and the virulent matter (of which there was but little) carefully re- 

 moved and placed in a porcelain capsule. About five minutes after its 

 removal, four young shoots of the lilac, a small horse chestnut of one 

 year's growth, a corn plant, a sunflower plant, and a wild cucumber 

 vine, were vaccinated with it. The vaccination was performed by the 

 dipping the point of the penknife into the virulent matter, and then 

 inserting it into the plant, just beneath the inner bark. No visible 

 effects, in either case, of the influence of the poison were perceptible, 

 till about sixty hours after it had been inserted. Soon after this, 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, if they 

 had not been marked, where the poison was inserted. Ninety-six 

 hours after the operation, nearly all the leaf-blades in each of the plants, 

 above the wounded part, were wilted and 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 seventh 

 day they were about as they were on the sixth. On the tenth day 

 they began to show slight signs o*f recovery. On the fifteenth day, 

 new but sickly-appearing leaves began to show themselves on the lilacs, 



