88 



THE VENOM OF HELODERMA. 



In another experiment the piece of venom gland was placed under the skin 

 into the subcutaneous tissue of a turtle's leg. Two days after the transplan- 

 tation, when the turtle seemed to be dying, the piece of gland was removed; 

 part was reserved for histological study and another part divided and inocu- 

 lated into two mice. Both of these mice died 45 minutes after the inoculation. 

 (The turtle died on the following day, that is, about 2.5 days after the gland had 

 been placed under the skin.) Even in the turtle the fluid of the venom gland 

 of the Heloderma retains its toxicity for a period of 2 days. 



IMMUNIZATION AGAINST HELODERMA VENOM. 



By giving repeated and constantly increasing doses of venom an attempt 

 was made to immunize animals against the venom of the Heloderma. For this 

 purpose rabbits, pigeons, and geese were used, the latter animals because they 

 were reputed to be resistant to various venoms, and especially to certain bac- 

 terial infections. 



In immunizing the geese, we injected into the pectoral muscles of the ani- 

 mals very small doses (0.05 c.c.) of the fresh venom. The first or second 

 injection appeared to produce no effect, so that the quantity of venom was 

 increased to 0.07 c.c., and in every case the animals died after the third or 

 fourth injection. The attempt to immunize geese against venom was given 

 up after all four geese used in these experiments had died.* 



Immunization of rabbits against heloderma venom. 



With the ten pigeons used in these experiments we were somewhat more 

 successful. 0.5 mg. of venom was given at the first injection, this dose produc- 

 ing no distinct effect. At periods varying from 1 to 33 days after this first in- 

 jection a second injection of a like quantity of venom was given. Four pigeons 

 died after the second injection of 0.5 mg. of venom. The six remaining pigeons 

 received, 5 to 7 days after this injection, 0.6 mg. of venom, and thereafter, every 

 5 or 10 days, slightly increased doses of venom. Four of the remaining pigeons 

 died; one after three, one after six, one after seven, and one after eight injec- 



*In repeating these experiments, it will be advisable to use dried instead of fresh venom, in order to eliminate 

 the variations in the strength of the venom as a complicating factor. 



