54 THE VENOM OF HELODERMA. 



of them rats and guinea-pigs were used in testing the comparative strength of 

 venom obtained with and without pilocarpine. The venom collected after 

 injection of pilocarpine was at least as active as the venom obtained without 

 pilocarpine. 



Influence of injection of Pilocarpine on secretion of venom in Heloderma. 



Experiment 1 (May 14): 



10 h 15 m Inserted rubber in mouth; rapid flow of saliva. 

 10 25 Diminishing flow. 

 10 30 Flow ceased; 2 c. c. collected. 



10 30 Injected 0.1 grain pilocarpine in 1 c.c. physiological salt solution; animal shows 

 immediate weakness; ceases to bite; no flow of saliva. 



10 40 Flow of saliva beginning. 



11 00 Good flow; mucus increasing; animal again bites well. 

 11 15 Flow finished; about 2 c.c. collected. 



Experiment 2 (May 20) : 



Collected nearly 1 c.c. of saliva from large heloderma during 20 minutes; injected 0.1 

 grain pilocarpine in 1 c.c. physiological salt solution; collected nearly 1 c.c. 

 during next 20 minutes; urine and feces voided; no marked signs of weakness. 

 Experiment 3 (May 20): 



Collected nearly 1 c.c. saliva from large heloderma in 30 minutes; injected 0.1 grain 

 pilocarpine; flow began in about 5 minutes; collected in 15 minutes about 2 c.c; 

 became viscid and flow diminished; collected in next 15 minutes about 1 c.c. 

 Experiment 4 (May 31 ) : 



Collected during 30 minutes about 0.7 c.c. saliva from one large heloderma; secretion 

 ended, injected 0.1 grain pilocarpine; 5 minutes later secretion began again; 

 during 30 minutes collected 1.5 c.c. 

 Experiment 6a (June 12): 



Collected venom from 8 helodermas; got from 8 only about 0.4 c.c; gave 2.1 grains each 

 of pilocarpine; collected about 1.4 c.c. 

 Experiment 6b (June 13): 



Injected same helodermas with pilocarpine; one gave no venom before or after injection; 

 the other was not tried before, but gave after injection only about 0.2 c.c; all 

 helodermas not tried on the 12th were tried and gave practically no saliva; to 

 be fed to-night. 

 Experiment 6c (June 14): 



Two helodermas injected with pilocarpine on third successive day; no secretion. 

 Experiment 6, cont. (June 17): 



One heloderma that received pilocarpine on three successive days (June 12-14) dead. 

 Experiment 7 (June 18): 



Took venom from all helodermas (18) ; 4 that have been in the laboratory and have 

 eaten two successive nights gave most of it; 2 were injected with pilocarpine; 1 

 which had given none before gave scarcely any, the other (one that had been in 

 the laboratory) gave the usual increased secretion; collected altogether onlv 

 2.2 c.c 



Comparative toxic effect of venom obtained with and without injection of pilocarpine. 



Guinea-pig 29, 100 g. 



May 20, 4 h 12 m injected 0.066 c.c. venom of heloderma No. 1 in 1 c.c. physiological 

 salt solution; secretion obtained before injection of pilocarpine. 5 o'clock 

 weak; breathing slow, not difficult. 6 o'clock dead. 

 Guinea-pig 28, 500 g. 



May 20, 4 h i0 m injected 0.066 c.c venom from heloderma No. 1 obtained after 

 injection of pilocarpine. 5 o'clock paralyzed; breathing slow and quiet. At 

 6 o'clock dead. 

 Guinea-pig 31, 500 g. 



May 20, 4 h 16 injected 0.066 c.c. venom from heloderma No. 2 obtained before 

 injection of pilocarpine. 5 o'clock animal affected, sits upright, able to right 

 itself when put on side. 6 o'clock symptoms grave; not likely to recover. 

 May 21 found dead. 

 Guinea-pig 32, 480 g. 



May 20, 4 h 14 injected 0.66 c.c. venom from heloderma No. 2 obtained after 

 injection of pilocarpine. First portion before secretion of mucus was abundant. 

 5 o'clock paralyzed; breathing quick, not difficult. 5 h 20 m dead. 



