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PHYSIOLOGY AND TOXICOLOGY 



pigeon's woundod wing allowed to fall upon it. They were instantly mixed. 

 Within three minutes the mass had coagulated firmly, and within ten it was of 

 arterial redness. 



Experiment. — One drop of arterial blood from the pigeon was mixed with one of 

 venom. Coagulation took place as usual, but the blood did not darken. 



The last experiment was repeated, substituting venous blood, coagulation ensued, 

 and on exposure the blood became of arterial redness. 



Experiment. — Two drops of venom were added to one of pigeon's blood. Coagula- 

 tion took place within four minutes. Pure blood from the pigeon was frequently 

 found to coagulate a little sooner than this. So small a degree of retardation may 

 have been due to the thiclv and gummy nature of the admixed venom. 



As I was anxious to verify these observations, I instituted a number of experi- 

 ments, some of which are briefly stated in the table below. Simple as the conduct 

 of such experiments may seem, they are liable to fallacies. If, for instance, care 

 be not taken, the blood coagulates before time is allowed to mix it with the venom. 

 Or again, the mechanical process of mingling is carried on too long, and the feeble 

 clots which alone are formed in the case of some animals, may thus be so broken 

 up as to escape notice in the minute amounts of blood we are compelled to employ. 



The specimens of blood described in this table were usually set aside after coagu- 

 lating, and the watch-glasses in which they were placed remained covered with 

 smaller ones during twenty-four hours, the temperature being from 78° to about 

 82° F. To my surprise, the clots, which were in some instances very firm, became 

 in all more or less altered during this period of time. The blood was darker, the 

 structure of the clots softened and partially or entirely dissolved. 



It becomes clear from these results that the mixture of venom and blood does not 

 alter the vital fluid at first in any way which is appreciable to our senses. The blood 

 drawn into venom and rapidly mixed with it in any proportion, clots as firmly as 

 usual. After a time, however, it seems that a catalytic change is induced, the clot 

 softens, and even becomes perfectly redissolved when the amount of mingled venom 

 has been large and the temperature of the air high. This alteration of the formed 

 clot, external to the body, finds its illustration within the system in those cases of 



