86 THE VENOM OF HELODERMA. 



each receiving 1 to 2 c.c. blood. After 1 minute 40 seconds there was the 

 beginning of coagulation in the tubes and 8 minutes after the withdrawal of 

 the blood the coagulation in the test-tubes was completed; 3 minutes later the 

 blood in the porcelain dish was a solid coagulum. In a control experiment 

 we withdrew in a similar manner, directly after death, the blood from a rabbit 

 whose neck had been broken. In this case the blood escaped more slowly from 

 the heart and consequently came into a prolonged contact with the tissues. 

 Coagulation here was completed in 1 minute 25 seconds. 



In a third experiment the same venom-gland extract was used after it had 

 been standing on ice for several days; 30 seconds after the intravenous injection 

 of 1 c.c. of the extract, the rabbit, weighing about 2,200 grams, was weak and 

 its respiration forced; 3 minutes after the first injection a second injection of 

 1 c.c. of venom was given; 6 minutes after the second injection the animal died 

 and the blood was withdrawn through an incision into the heart; after 1 minute 

 10 seconds the blood was coagulated in the porcelain dish and almost coagu- 

 lated in the test-tubes. In the latter the blood had been shaken during the 

 process of coagulation and the clot somewhat retracted. In consequence of 

 this premature retraction some blood remained fluid in the test-tubes; this 

 blood became solid 3 minutes after the formation of the first clot. 



We may conclude from these experiments that after injection of the gland 

 extract an exceedingly slight retardation in the coagulation of the blood may 

 take place. It is, however, very doubtful whether this retardation is to be 

 attributed to a specific effect of the venom; it is more probably due to the 

 influence of tissue extract, which produces a negative phase if injected in very 

 small quantity. However that may be, at the best the effect of the injection of 

 gland extract on the coagulation of the blood was very small in our experiments. 



In contradistinction to the venom of Heloderma various snake venoms 

 have a pronounced action on the coagulation of the blood, some venoms accel- 

 erating, others inhibiting it. 



INFLUENCE OF INOCULATION OF PIECES OF VENOM GLAND INTO MICE. 



In the course of some work concerning the growth of pieces of the venom 

 gland transplanted into helodermas, the retention of the toxicity of the venom 

 in the transplanted pieces of gland was also studied. In order to determine 

 this, pieces of venom gland were inoculated into mice. The details of the 

 transplantation of these pieces of gland will be found in a previous paper deal- 

 ing with the morphology. It will be sufficient here to state that pieces of the 

 gland were placed under the skin of the same animal's thorax and at the same 

 time under the skin of another animal's thorax, so that each animal had two 

 grafts. The first mentioned piece will be spoken of as the auto-transplant, the 

 second as the iso-transplant. Four experiments were carried out in which the 

 pieces were removed 1, 2, 3, and 4 weeks respectively after the transplanta- 

 tion, and were then inoculated into mice. The pieces of venom gland were 

 placed under the skin of the mice by means of a trocar and canula in a manner 

 similar to that by which the routine mouse-tumor inoculations are made. 



