214 THE VENOM OF HELODERMA. 



for testing the adsorptive power of the various substances, we injected in each 

 mouse quantities of the supernatant fluid which should have contained between 

 0.050 c.c. and 0.005 c.c. of venom, provided no venom had been adsorbed by the 

 substance tested; it having been shown that the smallest of these doses of 

 venom was sufficient to kill a mouse. 



In the case of dissolved dry venom we injected either 2 c.c, 1 c.c, or 0.5 

 c.c. of the solution after separation from the adsorbent particles. The small- 

 est dose injected should, therefore, have contained 0.5 mg. of venom, which is 

 approximately 3§ times the lethal dose. 



In the first experiments we used the fresh venom; but in all our later 

 work the dissolved dry venom, which was more uniform in its action, was 

 employed. 



In testing the toxicity of the residue, we used that portion of the mixtures 

 which had been thro\vn dowTi by the centrifuge after the supernatant fluid had 

 been decanted (or in the case of oils, the surface layer). This residue was 

 shaken up with 0.85 per cent sodium-chloride solution and again centrifuged. 

 After the second centrifugation the supernatant fluid containing the venom 

 which had perhaps been retained between the adsorbent particles, was poured 

 off and the residue added to 7 c.c. of salt solution. Thus the residue was sus- 

 pended in a quantity of non-toxic fluid equal to the original venom solution, 

 and anj^ toxic effect of this emulsion could justly be ascribed to the venom 

 adsorbed by the particles. In each case 2 c.c. of this emulsion corresponding to 

 183 lethal doses, provided the venom had been entirely adsorbed, were injected 

 into mice. 



In each series of experiments some control mice were injected with the 

 same quantities of the venom solution. 



ADSORPTIVE POWER OF CARMINE. 



The adsorptive power of carmine was tested with fresh diluted venom. 

 Venom solution, mixed with a quantity of carmine equal to half its volume, 

 entirely lost its toxic action. Three mice injected with quantities of the super- 

 natant fluid, which, had no venom been adsorbed, should have contained from 

 one to ten lethal doses of venom, survived the injection. In one experiment 

 the venom solution mixed with a quantity of carmine equal to one-quarter of 

 its volume was injected into two mice in quantities corresponding to two and 

 six lethal doses respectively, and both survived the injection, although both 

 were slightly affected. In another experiment the supernatant fluid derived 

 from a mixture of carmine and only one-eiglith of its volume of venom solution 

 was injected into mice in quantities corresponding to a little more than two and 

 six lethal doses. The first survived the injection and the second died. 



According to these experiments, carmine, when present in sufficient quan- 

 tity, adsorbs the heloderma venom completely or almost completely. A 

 quantity of carmine equal to one-eighth of the volume of the venom solution 

 adsorbs more than half of the venom. 



