178 C. J. MARTIN. 3 
On no occasion have I been able to prevent coagulation altogether, 
as was done by Weir Mitchell and Reichert! with the venomd 
the rattle-snake. These authors drew the blood directly intos 
vessel containing a solution of venom (a stronger solution than : 
mine), surrounded by a freezing mixture. On allowing the 
temperature of the blood to rise gradually they found it remained q 
permanently fluid. , : 
Examination of samples of blood exhibiting the negative : 
variation. ‘ 
Negative phase blood always shows marked retardation in : 
clotting. The delay is so great in some cases that putrefaction : 
sets in before coagulation has occurred. The loss of coagulability 
is the more pronounced the greater the amount of venom which 
has been introduced. There is not the slightest difficulty in pro 
ducing this negative phase ; it is only necessary to introduce the 
poison sufficiently slowly at first, in order that the initial positive 
variation may not reach the pitch when intravascular = 
occurs. 
a ae ey 
The blood of the negative phase takes up oxygen and gives it 
up in the usual manner, and with the exception of its loss of 
spontaneous coagulability, and the fact that some of the heemog!¢ 
is dissolved in the plasma, does not obviously depart huge 
-normal. In my examination of this blood, the corpuscles . 
separated from the plasma by the centrifuge. The — a 
which the coagulability of the plasmas was diminished % 
according to the amonnt of venom which had been in eu 
and also, to some extent, according to the time which had me 
between the injection of the venom, and the withdrawal of 
sample of blood. In most cases I found that the greatest of 
in clotting occurred in blood drawn about an hour after the 
duction of the poison. By increasing the dose of venom, be i 
been able to obtain plasmas in which coagulability was m 
to any degree, from slight delay in the onset of clotting, gett 
= 
1 Loe. cit. 
