260 C. J. MARTIN AND J. MCGARVIE SMITH. 
of the solution, until we repeated our experiments under circum- 
stances in which much greater accuracy was possible, viz., by 
using the minimal fatal dose and direct introduction into the 
venous circulation. 
The following experiments illustrate this diminution in toxic 
power:—Six guinea-pigs of nearly equal weight were taken and 
the minimal fatal dose of the poison was ascertained by injecting 
into the jugular vein of the first 34> grain, into the second +> 
grain. Both these animals suffered from convulsive movements 
which gradually decreased in severity and they recovered in four 
to five hours. The third guinea pig received ;4>5 grain, which 
caused death in sixty seconds. 
The three remaining pigs each received an intra-venous injec- 
tion of a solution of the poison which had been momentarilly 
raised to 100° C. One of these latter received an amount of the 
solution =z;'55 grain, and two others =;4>5 grain. Al! three 
suffered from some twitching, but none died, in fact in three hours. 
one could not detect anything wrong with them. 
We have been unable to detect any chemical change in the 
solution on heating to 100° C. with the exception of the coagula- 
tion of the albumin, which we have reason to believe is not possessed 
of poisonous properties, and cannot therefore attribute the diminu- 
tion in toxic strength of the solution to this cause. The boiled 
solution even when boiled for several days, by placing in a small 
flask with a little vertical condenser attached to it, and surround- 
ing the flask by a water bath, still contains proteids in solution 
which possess the same chemical characters as before, though it 
has lost its physiological importance. This effect of heat on Black 
snake venom, is similar to the results obtained by authors for the 
venoms of American and Indian snakes. 
Mitchell and Reichert found that heating the solution pro- 
duced a continued impairment in its toxic power even after the 
separation of the “globulin” by coagulation, which occurred 
below 75° C., and attributed this to the action of heat on the 
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