SNAKEBITES AND POISONOUS FISHES. 123 



This antitoxic serum is prepared in the following manner. Injections 

 over the shoulder were given to healthy horses subcutaneously of a solution 

 of dialysed venom in increasing doses for a period extending over months, 

 generally sixteen, each injection usually producing severe local reaction and 

 abscesses. When the horse is sufficiently immunised, he is bled from the 

 jugular, the blood is kept in a dark room for twenty-four hours, after 

 which the serum is syphoned off, divided up into 10 c.c. bottles ; these are 

 sterilised at a temperature of 10° C. on three successive days, the bottles 

 being kept in a dark room, as is necessary with all other antitoxic serums, 



The serum is useless for therapeutic purposes unless it is able to prevent 

 death in a rabbit when given intravenously in a dose of 1"5 c.c. 



It was found that the antivenine, like the toxin of the venom, is mainly 

 carried by the leucocytes and not by the serum, for if the effusion from the 

 peritoneal cavity of a vaccinated rabbit in which peritonitis has been excited 

 be centrifugalised, the leucocytes which are deposited are found to possess a 

 high antitoxic power, while the plasma has but little. 



If the antitoxic serum be heated above 68* C, it becomes coagulated and is 

 useless. 



The practical results of the late investigations may be thus briefly stated : — 



(1) That the injection of a sufficient dose of antivenomous serum (10 to 

 20 c.c.) prevents the toxic action of a lethal dose of venom given later, as 

 would occur frequently when a ligature was applied above the bitten part at 

 once, the venom having been kept out of the general circulation until after 

 the patient had been injected with the serum. 



(2) That the injection of a sufficient dose of the serum prevents intoxi- 

 cation by a lethal dose of venom given subcutaneously before, provided too 

 long an interval has not occurred, which would include those cases where a 

 ligature was not employed, or had been imperfectly applied, so that the 

 poison had gained access to the general circulation. 



(3) That as the resistance of man to the toxic action of the venom is 

 greater as compared with the smaller animals, a much smaller dose pro- 

 portionally of the serum is necessary to counteract the toxin. 



(4) That if the venom has been injected directly into a vein, the result 

 is always fatal, unless the serum be injected intravenously before or at the 

 same time. 



(5) That the serum should be at hand in all districts where snake-bites 

 are common, and that the inhabitants should be instructed in the advantages 

 derived from its use ; particularly as the amount of venom usually injected 

 by the snake is little above the minimum lethal dose, an interval of one to 

 three hours being in most cases allowable between the time of the bite and 

 the injection of the serum. 



(6) That when toxic symptoms are already present, the serum should be 

 xt once injected intravenously. 



