113 



THE RENDERING OF ANIMALS IMMUNE AGAINST THE YENOM 

 OF THE COBRA AND OTHER SERPENTS, 



AND ON 



THE ANTIDOTAL PROPERTIES OF THE BLOOD SEEUM OF THE 

 IMMUNISED ANIMALS. 



Communicated to the Royal Society of Edinburgh, June Srrf, 1895, 



By Thomas R. Feaser, m.d,, ll.d,, p.b.s., 



Professor of Materia Medica and Climcal Medicine in the University of Ediaburgh. 



i^Ahstract.) 

 Traditions as to Immunity. 



One of the most striking and interesting of the many traditions and current 

 beliefs regarding venomous serpents is that a power may be acquired of 

 freely handling them without injury, and even of successfully resisting the 

 poisonous effect of their bites. The Psylli of Africa, the Marsi of Italy, the 

 Gouni of India, and other ancient tribes and sects were stated to have been 

 immune against serpents' bites, and to have been able to exercise a remark- 

 able influence over even the most venomous of these animals ; and those 

 attributes have been explained on the supposition that serpents' blood was 

 present in the veins of the members of these tribes and sects. In more 

 modern times, and, indeed, at the present day, the same belief is stated in 

 the writings of travellers ; and it has been expressed by poets and novelists, 

 and, among the latter, with a half-admitted conviction of its reality, by 

 Wendell Holmes in his Romance of Destiny. 



It may be instructive to associate with this belief in the possession, under 

 certain conditions, by human beings of a power successfully to resist the 

 poisonous effects of serpents' venom, and with the evidences in its support, the 

 further belief that venomous serpents are themselves protected against the 

 efOects of bites inflicted upon them by individuals both of their own and of 

 other species. On mere anatomical grounds it is diiBcult to understand how 

 serpents could escape the absorption of their own venom through mucous 

 surfaces, even admitting that absorption of venom does not occur in normal 

 conditions of these surfaces. Venom must, however, be so frequently intro- 

 duced into their bodies, in situations where absorption could not fail to occur, 

 by the bites inflicted upon them by other serpents, that the conclusion seems 

 inevitable that they possess some protective quality, without which, probably, 

 no venomous serpents would now be in existence. Not only have many 

 general observations been made in support of this belief, but it has been 

 proved to be correct by direct experiments, such as those made by Fontana 

 of Tuscany more than a century ago, by Guyon, Lacerda.Waddell, Kaufmann 

 and Sir Joseph Fayrer, 



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