34"^ i:fi-"ixts oi' sxaki'. \i-;\(jm.s o.x noMi-.siii animals. 



venom was due to the fact that the venom used in its preparatioit. 

 being of Cokibrine origin, contained ahnosl i)ure neurotoxin, and 

 and ])ractically no hctmorrhagin. wiiiclt is the prejxjnderating 

 constituent in the \'ii)erine vencjm. 



Several pure sera have heen from time to time prepared 

 against the venom of particular snakes; the chief of these are as 

 follows : — 



Lan.ib's pure Xaja Iripiidians serum, which, is strongly anti- 

 toxic for cobra venom. 



Laml)'s [jure / "ipera nisscllli serum, antitoxic for Viperine 

 venom. 



Noguchi's j)ure Crolalas serum, antitoxic for Viperine 

 venom, but having no effect on cobra. 



Noguchi's pure . Incistrodon serum, antitoxic for Vi]:)erine 

 venom, particularly Aiidslrodoit. but no effect on Colu- 

 1>rine venou'. 



'J'he preparation of a ])ol\valent sertim has been attemjned 

 with fairly successftil results, Inu it is not yet possible to pre|)are 

 a serum sufficiently polyvalent to satisfy all requirements. 



Calmette ol)tained his serum from horses hy])erimmimised 

 against cobra venom in the following manner: — 



Small doses of the vencjm with hypochlorite of lime were 

 first injected subculaneously. The quantity of venom was gradu- 

 ally increased and the hypochlorite diminished, and injections 

 repeated ever)- three or foiu* da}.s, administration being regulated 

 by the condition (*f the animal. ]>ater a lieated mixture of cobra 

 and adder venoms was used containing 80 ])er cent, cobra and 20 

 per cent, adder. 



When the animal resists tlie injection of a minimal lethal 

 dose, the injections are pushed rapidly and continued until the 

 animal can withstand without ill-effects a subcutaneous injection 

 of 2 grammes of dried cobra venom — that is, about 80 times the 

 minimal lethal dose. During the immunisjition many complica- 

 tions arose, such as endocarditis, acute nephritis and abscess for- 

 mation. The time re(juired for the imiuunisation under favour- 

 able conditions was about 16 months. Senun was obtained from 

 an animal so treated, and tested, the serum being considered to 

 be sufficiently antitoxic when i c.c. of serum luixed with o.coi 

 gramme of cobra venom produced no symi)toms of intoxication 

 on subcutaneous injection into a rabbit, and \vhen 2 c.c. of serum 

 injected into a rabliit of 2 kilos, i)rotected it against an injection 

 of 0.00 1 grannne of venom two hoin-s later. 



The results oljtained from the use of Calmette's servmi have 

 been very good, Init it nuisi be remembered that the serum is 

 almost ])urely anti-neurotoxic, and if sitccessful restilts are to 

 be expected it can only l)e used in cases of bite by Colubrine 

 snakes. 



The necessity of a sertun whicii would protect against South 

 African snakes primarily was realised in iqoi by Watkins- 

 Pitchfortl, working in Natal, and he commenced the preparation 



