320 VENOMS 



the formula of which, according to the latter author, is said to be 



BufotaUn is readily soluble in alcohol, chloroform, acetone, 

 acetate of ethyl, and acetic acid. When water is added to a 

 solution of it in alcohol it is precipitated, giving a white emulsion, 

 which has a very bitter taste. 



From the aqueous extract whence the bufotalin has been 

 separated, it is possible to separate a second poison, which acts 

 on the nervous system and causes paralysis. In order to obtain 

 it in a pure state, the extract is treated with alcohol at 96^ C, 

 filtered and distilled ; the residue dissolved in water is defaecated 

 with subacetate of lead and sulphuretted hydrogen. The solution 

 thus obtained is successively exhausted with chloroform to extract 

 the cardiac poison, and with ether, which removes almost the 

 whole of the acetic acid. The second neurotoxic principle, called 

 hiifotenin, remains in the residue of the solution after being 

 evaporated in vacuo. 



Toad-venom, therefore, contains two principal toxic substances: 

 bufotalin, which is of a resinoid nature, soluble m alcohol, but 

 scarcely soluble in water, and is the cardiac poison; and hufoteiiin, 

 which is readily soluble in those two solvents, and is the neuro- 

 toxic poison} 



Proscher, on the other hand, has extracted from the skins of 

 toads a haemolytic substance, termed by him phrynolysin, which 

 possesses all the properties of a true toxin and is not dialysable. 

 It is obtained by pounding the skins with glass powder in physio- 

 logical serum. 



Phrynolysin dissolves the red corpuscles of the sheep very 

 rapidly, and (in order of sensitiveness) those of the goat, rabbit, 

 dog, ox, fowl, and guinea-pig. The red corpuscles of the pigeon, 

 frog, and toad are scarcely affected. When heated at 56" C. it 



' " Rapports des venins avec la biologie generale," Bevue generate des 

 Sciences, December 30, 1903. 



