THE EFFECTS OF SNAKE VENOMS ON DOMESTIC 

 ANIMALS, ANU THE PREPARATION OF ANTI- 

 VENOMOUS SERUM. 



By Daviu Thomas Mitchell, M.R.CA'.S. 



From time im.memorial, and among all races, even where a 

 fairly advanced state of civilisation existed, snakes have been 

 looked upon as objects of dread and typifying mystery and wis- 

 dom. In more recent years, the progress of science has to a 

 great extent dispelled the feeling of fear and repulsion which is 

 associated with snakes, but yet it is impossible to regard without 

 feelings akin to dread an animal which is capable of biting and 

 causing changes which may result in the death of even the strong- 

 est animal in a very short space of time. 



The nattire and mode of action of the more common snake 

 venoms has been the subject of careful research in the last qttarter 

 of a century, and the results have been very hopeful. It has 

 been found that the active principles of snake venoms are soluble 

 l)roteids belonging to the same class as enzymes and toxins. It 

 has also been ascertained that immunisation can be carried out 

 in the same way as in the immunisation of animals against 

 contagiotts diseases, and that the serum taken from animals so 

 immunised possesses anti-venenes wliich are specific. In order, 

 therefore, to be successful in the treatment of snake-bite with 

 such serum, it is necessary to have some idea of the species of 

 snake which has inflicted the bite. For this rear.on I propose, 

 before entering into the question of venoms and anti-venomous 

 .seriuu, to give a short classification of venomous snakes. 



Reptiles of the order Ophidia, to which snakes belong, are 

 distinguished by their elongated limbless bodies covered with 

 horny epidermal scales, by their extremely flexible mouth, by the 

 absence of eyelids, of a tympanic cavity and external ear open- 

 ings, by having the cloacal orifice transverse and the penis paired, 



For the accurate identification of the various families and 

 genera it is necessary to be acquainted with the terminology of 

 the scales, especially those covering the head, and also to know 

 something about the skull and dentition, but as tliis would take 

 up too much space, it is not my intention to enter into this subject 

 in detail. 



There are about 1,700 species of snakes known, of which 

 some 300 have efficient i)oison fangs, and so must be classed as 

 venomous, while 300 more possess a type of grooved tooth, and, 

 therefore, while they cannot in the true sense be called venomous, 

 as they are capable of instilling a secretion — whether saliva or 

 venom — into the wound made, they nuist be regarded with suspi- 

 cion. These species are distributed atnong nine families, two of 

 which include the venomotis and suspicious species. In the light 

 of past experiences it is well, however, to avoid completely ignor- 

 ing those varieties which are looked upon as harmless. 



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