THE SKIN AND SENSE ORGANS 293 



(1908), and Theis (1932) may be consulted. Ancel showed that the 

 poison glands were of ectodermic origin, while Nierenstein held that 

 they arose secondarily from degenerating mucus glands, a view with 

 which Esterly — for Plethodon — agrees. Recently, however, Theis 

 has reinvestigated the whole question and concludes that there is no 

 transition from mucus to poison glands. 



When a Salamander is irritated, e.g. by chloroform, a white milky 

 fluid is seen to exude from the venom glands. This substance is a fairly 

 potent irritant poison and eventually causes paralysis in the victim. 

 Although there is no mechanism whereby the animal can inject the 

 poison into a victim, and it must therefore remain a purely defensive 

 weapon, nevertheless the Salamander can, on occasion, squirt or spray 

 the fluid to a surprising distance, quite sufficient to get into the eyes 

 and nose of a too inquisitive marauder. Probably this action is 

 efl'ected by means of the smooth muscle elements which invest the 

 glands (cf. also Esterly, 1904). 



3. Venom. 



A fairly considerable amount of work has been carried out in an 

 endeavour to elucidate the chemical nature of the poison, and two 

 alkaloids have been isolated from it in a pure state. The first worker 

 in this field was Zalesky (i 866) who isolated the chlorhydrate of one 

 of them, which he called Samandarin^ and suggested for it the formula 

 CggHeeOioNa. His choice of name was due to a suggestion by Prof. 

 Roth of Tubingen that the Greek word araXafjidvSpa comes from 

 the Persian Samandar, a similar word occurring in both Arabic 

 and Hindustani. Zalesky also investigated its physiological eff"ects. 

 The next worker was Faust (1898 and 1900) who isolated the sul- 

 phate of both alkaloids. To Samandarin sulphate he gave the formula 

 C52H80N4O2+H2SO4 or (C26H4oN20)2+H2S04. The second base 

 he named Samandaridin and suggested the formula (C2oH3iNO)2+ 

 H2SO4 for its sulphate. He supposed that they were both built 

 around the methyl pyridin group C5H5(CH3)N and that Samandarin 

 has more of these groups than Samandaridin. He also found that the 

 pharmacological strength of the former was 7-8 times greater 

 than that of the latter. Gessner (1926), and Gessner and Craemer 

 (1930) have recently made a fresh analysis of the Salamander venom 

 and have isolated both substances in the pure state. Their analysis of 

 Samandaridin does not quite agree with that of Faust, having one 

 atom of carbon less and one atom of oxygen more than his, namely, 

 C19H31 O2N, with a freezing point of 187° C. 



It is not proposed to catalogue the numerous pharmacological and 



