KFFKfTS Ol-- SNAKK \HN(1.MS (>\ DO.MI'STR' AXiMALS. ^4/ 



exception of a horse bitten ])y i'aitsns rhoiiibcal its. which animal 

 was onl}' very shqlitly affected 1>v the bite. 



The nervous syni])tonis conUl not l^e easih' (hstinguishe'V 

 from those produced by Coliibrine venom. Dej^ression occurred 

 in the earh'er stages, and this w:is later followed by twitching of 

 the skeletal muscles, frecpient defa?cation anci micturition, spas- 

 modic contractions of the abdominjil and limb muscles being 

 noted in some cases. The ])ulse was fref|uent '.\u(\ weak, and the 

 respiration laboured. Death was preceded b}' a comatose con- 

 dition, in which stertorous breathing and a weak, infrequent 

 pulse were the ])rincipal features. 



No .symptoms of incoorditiation of movement or paresis 

 were observed. 



In the posl-inorteiJi examination it v/as found that the 

 tissues underlying- the skin at the site of the bite were infiltrated 

 and h?emorrhagic. Blood-tinged exudates occurred in the serous 

 cavities. Hypera^mia of the lungs and bronchial tubes was 

 present, and hsemorrh.agic areas were present in the alimentary 

 tract. 



Exann'nation of the blood obtained from animals recently 

 l)itten by (.'aiistis rhouibcatus and Bitis aricfaii^ showed that the 

 venom produced no h3?molysing effect on the corptiscles, nor 

 was any diminution of coagulability of the blood apparent in 

 l)lood acted on by the venom of Causus rhouibcatus. A marked 

 anti-coagidative effect was. however, jirodticed in the l)1ood of 

 animals l)itten by t'itis ancfaus. 



Having now consi<lered the com])osition and ])l:ysiological 

 actions of snake venoms, the next points which come to be dis- 

 cussed are immunitv against veufun and the ])reparation of anti- 

 venomous serum. 



vSewall in i^^y made the first scientific attempt to produce 

 artificial immunity, when he imnninised pigeons by rei)eated 

 r.mall doses of venom, so that th.ev ^vere able to withstand lo 

 minimal lethal doses of Cr<>tal'.is venom. 



Experiments on similar lines fr)llowed, and in iS(;2 Calmette 

 showed that by repeat e<I injections of venom, heated to (So 

 degrees Centigrade, a ot.nsiderable amount of resistance could 

 be ])roduced in animals. Horses were utilised for these experi- 

 ments, and a serum was ])roduced later. 2 c.c. of which were 

 capable of protecting a rab])it of two kilos, weight injected two 

 hours later with one milligram of cobra venom. Control un- 

 treated rab1)its. injected with a simitiar dose of venom only, 

 succmnbed in ^^o nn'nutes. h^razer, of b^dinburgh, confirmed these 

 results, and it was considered by him that this serum was ca])able 

 of jirotecting against all venoms. 



It was later shown by I,aml> that, although Calmette's 

 serum was active ag;iinst cobra-venom, it, was not ttseful against 

 Mperine venom. Me also showed that ;i preci})itin was present 

 in anti-venomous serum, and he asstinied that these principles 

 were specific. 



The failure of Calmette's scnnn to protect against X'iperitie 



