SNAKE ANTITOXINE. 231 



manner, the toxine could be removed from the mixture by 

 precipitation with calcium chloride, so that the previously neutral 

 serum again had a protective action (1896). These results, which 

 are extremely important from the theoretical point of view, have 

 been conditionally confirmed by MARTIN and CHERRY, 3 who were 

 able, under certain conditions, to effect a separation of the 

 poison of Hoplocephalus curtus from the antitoxine by heating 

 the mixture to 68 C. 



Thus, when the components of the mixture have only been 

 allowed to act upon each other for a short time, or when a 

 relatively large amount of poison has been used, CALMETTE'S 

 statement is correct ; the antitoxine is destroyed and the toxic 

 activity restored by heating the mixture. After fifteen minutes, 

 however, the combination is so firm that it can no longer be 

 broken up. Again, it is impossible to effect a separation by 

 filtration through a gelatin filter under pressure, which otherwise 

 allows the free toxine but not the antitoxine to pass, since no 

 part of the mixture passes through the filter. 



The conclusion that there is a simple combination is in no way 

 affected by the fact that, according to MARTIN, the dose that 

 combines with a definite quantity of snake venom in vitro is 

 much less than that required for previous immunisation when 

 injected subcutaneous^. The quantity is considerably greater 

 and may even amount to a thousand times as much. On the 

 other hand, only about the same quantity is required if intra- 

 venous injection be used. 



MARTIN attributed this to a much slower diffusion of the 

 antitoxine than of the toxine on subcutaneous introduction, the 

 toxine being also very rapidly distributed through the body by 

 way of the anastomosing lymph tracts. 



It is also worthy of note that CALMETTE (1895) found that 

 tetanus antitoxine and antiabrine had also a certain action upon 

 snake toxine, so that the serum would thus seem to be not 

 absolutely specific. On the other hand, the sera of animals that 

 had been treated with strychnine, curare, and various bacteria 

 proved as absolutely powerless against the venom as normal 

 human serum. 



Anti-snake-venom serum only becomes inactive when the 

 temperature reaches 68 C. Calcium chloride and gold chloride 

 do not affect its protective power. It can also be kept for a 

 long period without the addition of phenol. 



3 Martin and Cherry, " The Nature of Antagonism between Toxines and 

 Antitoxines," Proc. Roy. Soc., Ixiii. ; Martin, "Relation of the Toxine 

 and Antitoxine of Snake Venom," ibid., Ixiv., 88, 1899. 



