GENERAL PROPERTIES AND ACTIONS OF THE VENOM. 57 



The heloderma venom is rather more resistant to the destructive action of 

 heat than any of the above-named snake venoms, since even though heated to 

 120° C. the toxic action is weakened but not destroyed. 



Below we give a few experiments showing the influence of heating on the 

 toxicity of the venom. 



Boiled Venom (filtered). 

 Rat 12, 110 g. 



May 28, 3^ £3" injected 0.1 c.c. venom. 4 o'clock verj- weak, appears dj-ing. 

 4^ 30'" somewhat better. 5 o'clock a little better, able to slowly right itself if 

 placed on back. 6*' SO"" still living, condition ven,- bad. 6^ 25'" dying. 

 Found dead. 

 Guinea-pig 41, 400 g. 



May 27, Jf^ 23'" injected 0.1 c.c. venom. 6^ 35'" drowsy, occasional starts, able 

 to right itself when placed on side. 7 o'clock occasional con\-ulsive jerks, posi- 

 tion drooping. 8^ 30'" occasional violent jerks, position abnormal. May 28, 

 9 a. in. much improved. May 29 recovered. 

 Unboiled Venom. 



Rat 13, 110 g. 



May 28, 3^35'" injected 0.1 c.c. venom. ^ o'clock slightly worse than rat 12. 

 ^h go" improving, still worse than rat 12. .5 o'clock dying. 5'' 30'" dead. 

 Guinea-pig 41, 340 g. 



May 27, 4'' 30"' injected 0.1 c.c. venom. 6^ SC" forced breathing; lies on side; 

 very weak. 7 o'clock dying. 7^ 05" dead. 

 Precipitate from Boiled Venom used on May 28. 

 Rat 14, 100 g. 



May 29, 3^ 55'" injected. G o'clock rather sick. May 30, 9 a. m. found dead. 

 Boiled Venom (not fdtered) . 

 Guinea-pig 4.5, 800 g. 



May 29, 3^ -47" injected 0.2 c.c. venom. 5^ 30'" Ij'ing down, breathing labored. 

 5^ Ji5"^ dying, occasional jerking movements. 5^ 50'" convulsive jerking, ex- 

 tremely irritable. 6 o'clock dead. 

 Unboiled Venom. 



Guinea-pig 46, 700 g. 



May 29, S"" 55"^ injected 0.2 c.c. venom. 5'' JO" bad condition, slightly better 

 than guinea-pig 4.5. 6 o'clock djing. 6^ 05"' dead. 

 Venom Dried below 70". 

 Mouse 41. 

 Nov. 13, 2^ 20"' injected 0.2 mg. intraperitoneally. 4^ 25'" dead. 

 Same Dried Venom Heated 1 hour to 116°. 

 Mouse 45. 



Nov. 13, 3^ 15'" injected 0.2 mg. intraperitoneally. 5^ 30"' dead. 



EFFECT OF ST.\NDING IN SOLUTION ON TOXICITY OF VENOM. 



A 10 per cent solution of venom in physiological salt solution kept sterile 

 and allowed to stand for 9 days in the laboratory showed no decrease in viru- 

 lence; but venom sterilized and merely covered became, under the same con- 

 ditions, less toxic. This doubtless is due to the action of bacteria entering it 

 from the air. To guard against possible complications due to the presence of 

 bacteria in venom which had been allowed to stand, it was resterilized before 

 being used for inoculations. 



June 8 a quantity of venom was sterilized and its strength tested on a 

 mouse and a rat. It was divided into two portions, one of which was kept 

 sterile and the other simply covered, so as to prevent the entrance of dust. 

 Both portions were left for 9 days in the laboratory at room temperature and 

 in the light. On June 17 they were heated to 60° C. for 45 minutes and used in 

 the following ex]3eriments; 



