POISONOUS SNAKES OF NORTH AMERICA. 461 



other peculiarities, possessed the property of immediately precipitating 

 Prussian blue when treated successively with ferrocyauide of potassium 

 and tbe ferric salts. He expressly remarks, however, that these alka- 

 loids do not constitute the most dangerous part of the venom, which 

 he asserts is of a nitrogenous nature. Tliey seem chiefly to stupify, 

 but are not necessarily fatal. In the course of the discussion he fur- 

 ther emphasized the fact that these leucomaines in the normal state of 

 the tissues only occur in minimal proportions {torn. cit. p. 431). 



Other careful investigations simultaneous with and later than those 

 of Prof. Gibbs have fully substantiated the claim that the leucomaines 

 play no role in the poisoning, and that, if present, they form no essen- 

 tial part of the venom. Dr. AVolfenden {loc. cit. p. 335) made examina- 

 tions of cobra venom by the Stas-Otto method for ptomaine, or alkaloid, 

 in three diiferent instances, but did not succeed in finding- the slightest 

 trace of any sui!h body. There was neither trace of fixed nor volatile 

 alkaloid, the residues were noncrystalline and, moreover, nontoxic, and 

 gave none of tlie alkaloidal test reactions. 



Prof. Gautier, as I have already intimated, insisted that the toxic 

 constituent of the venom is of a different nature. The researches of 

 the last ten years have proved beyond a shadow of doubt their proteid 

 nature, and that Bonaparte was correct when, in 1843, he referred to it 

 as an albuminoid. 



The achievements during the last decade in the study of the chem- 

 istry ot snake venoms have been of such a nature, are so recent, and 

 even now progressing, that the best way to record them is to treat them 

 historically and chronologically. 



The first progressive step was taken when, in 1883, Dr. S. Weir 

 Mitchell and E. T. Eeichert, of Philadelphia, laid before the National 

 Academy a preliminary report on tlie results of studies, which, after a 

 lapse of twenty years. Dr. Mitchell had resumed. He had in some way 

 become convinced that the complexity of the symptoms in snake 

 poisoning could not be the result of a single simple constituent, but 

 that they might be explained bj^the assumption of a similarly comjilex 

 nature of the albumiuoid body, the crotaline, previously thought to be 

 simple. Dr. Mitchell, in a later popular article,* has given a clear and 

 interesting insight in the mental process which led to the important 

 discovery and the laboratory processes by which it was demonstrated, 

 from which v,e make the following abstracts: 



When I first studied tliis strange poison I thought of it as a single albuminous 

 body. As such it had always been regarded sinee it had been proved by Prince 

 Bonaparte to belong to the albumens. When once I chanced to think that venom 

 might be a complex fluid, holding in solution more than one poison, reasons for such 

 a belief multipliedj and so excited my interest that, in 1882, with Prof. Rei chert's 

 aid, I began to put my theory to the sharp test of experiment. To prove in the 

 outside laboratory what the inside mental laboratory has comfortably settled is not 

 always easy, and many mouths of careful research were required before the answer 



* Century Magazine, N. York, xxxviii, Aug. 1889, pp. 503-514. 



