106 THE VENOM OF HELODERMA. 



are very small as compared with the amounts produced when larger quantities 

 of fluid are retained. 



The diuresis corresponded to the blood-pressure curve in these experi- 

 ments. During the infusion of the first 100 or 200 c.c. of venom-ash sodium- 

 chloride solution the secretion of urine increased quite rapidly; and it continued 

 at about the same rate during the whole of the remainder of the period of infu- 

 sion. In this respect the venom-ash sodium-chloride solution produces approx- 

 imately the same effect as the pure sodium-chloride solution. The quantity of 

 urine secreted by the animals infused with venom-ash sodium-chloride solution. 

 is only slightly less than the amount secreted by the animals infused with 

 sodium-chloride solution, but is distinctly larger than the amount secreted bj' 

 animals infused vnth venom-sodium-chloride solution. 



The venom-ash exerts no distinct influence on either blood-pressure or 

 secretion of urine, and the changes observed must be due to organic substances 

 of the venom. 



In order to determine whether the lessened secretion of urine in the experi- 

 ments in which venom was added to the infused sodium-chloride solution was 

 due to the lowering of the arterial pressure, we carried out some experiments in 

 which we added adrenalin to the infused fluid. Adrenalin, when infused intra- 

 venously into animals, causes a rise of blood-pressure, and this rise is main- 

 tained during the whole period of the infusion; at the same time, adrenalin, 

 increases the diuresis.* 



In one experiment we added 1.5 c.c. of adrenalin to the 800 c.c. of sodium- 

 chloride solution which already contained 20 mg. of venom. In spite of the 

 presence of the adrenalin the infusion of the solution containing venom caused 

 in this case a very marked fall of the blood-pressure during the infusion of the 

 first 100 c.c. of fluid. Also in the later stages, after 400 or 500 c.c. had been 

 infused, the usual gradual fall of pressure was observed. In this experiment 

 adrenalin had little or no effect in preventing the action of venom on the blood- 

 pressure; neither had the diuresis curve been affected bj^ the addition of adre- 

 nalin, for we noted the early rise in the curve and the later fall coincident with 

 the fall in blood-pressure (see fig. 19). 



Three other experiments were made in a somewhat different manner. 

 The infusion was started with the usual venom-sodium-chloride solution (20 

 mg. of venom to 850 c.c. of sodium-chloride solution), and after either 150 or 

 200 c.c. of this mixture had been infused the adrenalin was added. In each of 

 two cases 1 c.c. of adrenalin (making thus approximately a 1 to 600,000 solu- 

 tion), and in the third experiment 6 c.c. of adrenalin (making a 1 to 100,000 

 solution) were added. 



In all these experiments the usual marked fall of blood-pressure was 

 observed when the first 50 or 100 c.c. of venom-sodium-chloride solution wore 

 infused. After the addition of the adrenalin (1 to 600,000) the blood-pressure 

 rose slightly, and it continued at approximately the same level until the con- 



•Flcisher .ind Locb, Jour. Expor. Med,, 1909, xi, 480. 



