276 



VENOMOUS ANIMALS 



(1) The specificity of snake- venom. 



(2) The inutility of an antiserum prepared for one venom against 

 another venom. 



It now remains to consider these subjects from a practical point 

 of view. 



The serum most readily obtained is Calmette's, in 20 c.c. and 

 50 c.c. phials standardized against cobra and Vipem russellii 

 venoms, and prepared by the immunization of horses against these 

 venoms, as well as those of Bungarus (krait) and Enhydrina (sea- 

 snake). Reliable sera are also prepared by tlie Indian Pasteur 

 Institute of Kasauli for the venoms of the cobra and Russell's viper. 



All these sera, unfortunately, deteriorate quickly unless kept in 

 a dark and cool place, and, further, must be used in large doses, 

 for even when fresh, i c.c. will only neutralize i milligramme of 

 cobra-venom. A healthy cobra when it bites may inject from 250 

 to 350 milligrammes of venom, of which the minimum lethal dose 

 may be estimated at 15 to 17-5 milligrammes for a person weighing 

 60 to 70 kilogrammes; therefore at least 350 c.c. of the antivenene 

 must be injected intravenously, or ten to twenty times that amount 

 must be mjected subcutaneously- — i.e., from 3,500 to 7,000 c.c. 



The antivenene, of course, will succeed in much smaller doses 

 if a small quantity of venom has been injected, and will fail if the 

 quantity be large. Therefore the obvious indication is to begin 

 with 100 c.c. of antivenene, injected hypodermically, or far better 

 intravenously, and to repeat this several times if necessary. The 

 technique for the intravenous injection is as follows: — 



An all-glass syringe should be carefully sterilized by boiling, and 

 the skin over the vein must be cleansed with i in 40 carbolic and 

 with absolute alcohol; a band should be tied round the arm, so 

 that the vein shows up clearly, and the needle should be inserted 

 with the aperture pointing proximally — i.e., towards the heart — 

 and should oe felt free in the vein. The ligature should then be 

 removed and the serum slowly injected. On removal of the needle, 

 an antiseptic pad and bandage should be applied. 



If, on the other hand, the species of snake which inflicted the 

 wound is known, and the particular serum for that animal's venom 

 happens to be available in good condition, then it should be used 

 intravenously. 



3. Treatment of Special Symptoms — (i) Failure of the Respira- 

 iion.— The experiments of Fayrer, Brunton, and Rogers seem I0 

 indicate that in cases of poisoning due to cobra and sea-snake 

 venoms artificial respiration should be resorted to when natural 

 respiration is failing and medical aid or remedies are being sent for. 



(2) Failure of Circulation. — In poisoning due to viper- venoms, 

 which produce, according to Rogers, a paralysis of the central vaso- 

 motor centre, he recommends that: — 



(a) A binder should be applied to the abdomen and bandages to 

 the legs, so that as much blood as possible may be available for 

 maintaining the circulation of the brain and medulla. 



