PROCEEDINGS OF THE ACADEMY OP [Biolog- 



Ofl ihe Physical and Chemical characteristics of Corroval and Vao, two recently 

 discovered varieties of Woorara, and on a new Alkaloid constituting their 

 active principle. 



BY WILLIAM A. HAMMOND, M. D. 



Assistant Surgeon U. S. Army, and 



S. WEIR MITCHELL, M. D. 



Lecturer nn Physiology in the Ihiladelphia Medical Association. 



The two new varieties of woorara, which, so far as relates to their 

 physical and chemical characteristics, we design considering at present, 

 were brought in February, 1857, from the Rio Darien, in New Granada. 

 by Drs. Ruschenberger and Caldwell of the United States Navy. By 

 these gentlemen they were presented to Prof. Joseph Carson, of the 

 University of Pennsylvania, to whom we must express our acknowledg- 

 ments for the opportunity afforded us of analyzing and experimenting 

 with these curious poisons. 



The corroval, the more powerful of the two, has the general appearance 

 of a vegetable extract of a brownish black color. The fracture is some- 

 what conchoidal, but some of the fragments in our possession have a sur- 

 face such as would be given to the superficies of an inspissated vegetable 

 infusion on cooling. When pulverized, itis of a tawny yellow appearance. 

 Its taste is an intense and very persistent bitter. The saturated aqueous 

 infusion is of a very dark brown, almost black color, and of neutral or 

 exceedingly slight acid reaction. The alcoholic tincture is of a pale 

 yellow tint. Both water and alcohol extract the poisonous principle, as 

 do also ether and chloroform, though to a very diminished extent. No 

 crystals are deposited from either of these solutions, except from the 

 ethereal. They consist entirely of fatty substances. 



The residue, insoluble in water, submitted to microscopical examination, 

 is seen to consist of vegetable cells, starch granules, portions of woody 

 tissues, oil globules, &c; small grains of silica are also to be observed. 

 No parts of animals of any kind can be discovered by most careful ex- 

 amination with object-glasses of high power and excellent defining quality. 

 If the fangs of poisonous serpents, the livers and other parts of the body 

 were used in the manufacture of con-oval, we should undoubtedly have 

 detected their anatomical elements. We therefore regard it as certain 

 that such substances do not enter into the composition of the material 

 under consideration. 



Corroval burns with a yellow flame, and gives off a considerable amount 

 of smoke and vapor. This latter has an odor very similar to that of 

 human excrement, and, as we have ascertained, possesses all the poisonous 

 activity of the corroval in substance. A mouse made to inhale the fumes 

 died in less than two minutes. Corroval heated upon platinum foil, in 

 the flame of the blow-pipe, is almost entirely volatilized. The ash con- 

 sists of silica, iron, and certain saline substances. 



In external characteristics vao cannot be distinguished from corroval. 

 That in our possession is a dark brown extract, hard, and perfectly 

 dry, and unaffected by exposure to the atmosphere. It yields its toxic 

 principle to water and alcohol, the infusions being of similar physical 

 qualities and reaction with those of corroval. The insoluble portion 



[April, 



