244 



VENOMOUS ANIMALS 



which may be exemplified by the Vipera russelUi. In addition, however, 

 there are venoms which show characters belonging to both types. 



Weir Mitchell alone and with Reichert indicated that there was a difference 

 between viperine and coin brine poisons; and C. J. Martin, working on 

 Pseudechis, a colubrine snake, discovered the intravascular clotting, and 

 suggested that the sudden death caused by Vipera russellii might be due 

 to this cause, which hypothesis Lamb and Hanna confirmed. 



The difference in the working of these two classes of venoms is still further 

 accentuated by the researches of Rogers, and later by those of Lamb, which 

 clearly prove that Calmette's antivenene will neutralize the colubrine, but 

 not the viperine, venom. 



In 1902 a most valuable paper appeared, by Flexner and Noguchi, showing 

 that, in addition to the neurotropic principles, the venom contained agglutinins 

 for the erythrocytes and for the leucocytes which were probably identical, 

 and lysins for erythrocytes and leucocytes which were separate. 



They also pointed out that venom contained haemorrhagins, and lessened 

 the bactericidal powers of the blood. They showed that antivenene neu- 

 tralizes venom by removing the haemolytic and antibacteriolytic actions. These 

 results have been confirmed and extended by Kyes, Sachs, Lamb, and others. 



The position at the present time is that, though snake-venom is extremely 

 complex, still, three kinds of venom may be recognized : — the colubrine type, 

 the viperine type, and the mixed type. In this last both colubrine and viperine 

 types are represented, but one is predominant. It is probable that the main 

 action of both types is on the nervous system, but that other principles in the 

 venom may mask this important action. 



With regard to treatment, there is no doubt as to the value of Calmette's 

 serum in cobra-poisoning, and Lamb's serum in cobra and Vipera russellii 

 poisoning, though the old method of ligature and incision, together with the 

 application of permanganate of potash, is still the most practically useful 

 method of treatment. 



Classification. 



The order Ophidia includes a large number of families, of which 

 only two are of importance to the tropical practitioner — viz., Colu- 

 bridae and Viperidae. 



FAMILY COLUBRID^ Boulenger, 1890. 



Defliiition. — Ophidia with ectopterygoids (transpalatines) and 

 supratemporals present with teeth in both jaws, but without coro- 

 noids, while the prefrontals are not in contact with the nasal bones. 



The Colubridae are divided, in works on snake poisons, into the 

 non- venomous and the venomous, and the latter are joined with 

 the vipers to form a subclass of the order Ophidia called Thana- 

 tophidia., or poisonous snakes; but this classification is by no means 

 satisfactory, as will presently be shown. There is no external 

 character, easily ascertainable, by means of which every poisonous 

 snake can be recognized and distinguished from a harmless snake. All 

 rules given to the contrary break down sooner or later, but the mouth 

 can be opened and the poison-fangs can usually be easily seen. 



The usual classification of the Colubridae is into three series: — 



I. Aglypha — Poisonous Colubridae possessing solid ungrooved 

 teeth. — The Aglypha are usually stated to be non-poisonous, but 

 the observations of Phisalix and Bertrand on Tropidonotus (sp. ?), 

 and Alcock and Rogers on Zamenis mucosus and Tropidonotus 

 piscator, prove that the saliva of these species is poisonous to rats, 



