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PHYSIOLOGICAL ACTION OF VENOM OF BLACK SNAKE. 937 
long incision at the outer border of the rectus muscle, and placed 
in Roy’s spleen box. Hot water was used to surround the organ, 
which was prevented from cooling in the same manner as before. 
In these experiments, however, the piston recorder was discarded 
owing to its insufficient range, and the end of the rubber tube 
farthest from the spleen box was connected with a small burette 
graduated in 34;ths of acc. The level of the water in the burette 
was adjusted so as to be three inches above the level of the spleen 
box, in order that the pressure on the outside of the organ should 
approximately equal the pressure in the splenic vein. During 
the progress of the experiment, the graduation opposite the level 
of the water in the burette was read off by an assistant, and at 
the same time an indication was made on the blood pressure record 
by raising the signal line. An increase in volume of the organ, 
due to increase in the capillary pressure within the organ, is 
indicated by the water flowing into the burette. Diminution in 
volume is indicated by a corresponding flow out of the burette. 
By reading off the increase or diminution in the water in the 
burette, a measure of the alteration in volume is obtained. 
In tabulating the graphic records, the height of the arterial 
Pressure curve has been measured as before, and in the spleen 
volume experiments, the volume in cc. by which the organ was 
diminished, has been placed opposite the value of the arterial 
blood pressure at the moment. With the kidney experiments the 
value of the ordinates on the curve in cc. was ascertained by 
observing the extent of rise or fall of the lever of the piston 
recorder which corresponded with the entrance or exit of | ce. 
of fluid into the piston box. This tabulation is not quite accurate, 
Owing to the lever moving in an are, and therefore the value of 
the ordinates is not uniform, but this error may be neglected 
for the present purpose. 
Tn observing the volume at any particular time, the maximum 
value and Minimum value of the respiratory undulations were 
both recorded and the mean taken. With the spleen experiments 
the Variations in volume caused by the rhythmic contraction of the 
