OF TUE VENOM OF THE RATTLESNAKE. 91 



chronic poi?oniiig, in which the fibrin of the blood, subjected to long contact with 

 venom, finally loses its power to coagulate. When under ordinary circumstances, 

 in summer weather, blood is protected from desiccation, the clot not unfrequently 

 softens after a few days, or even entirely redissolves. This change, however, is 

 produced by extensive putrefactive alterations in the blood, and is most readily 

 induced in the blood of such persons as are anajmic, or still more rapidly in the 

 blood of some reptiles and fish. The condition of difHuence attained within twenty- 

 four hours, under the influence of the venom, was such as usually requires, in pure 

 blood, several days of warm weather to effect. It is proper to add that in almost 

 all of the specimens of mingled blood and venom the odor made it evident that 

 putrefactive changes had taken place, an inference which was further justified by 

 the evidence which they soon afforded of continued progress in this direction. 



Fontana's^ observations on the subject of the direct action of venom on blood 

 are altogether insufficient and unsatisfactory. He seems to have been of opinion 

 that admixture with venom darkened the blood, and prevented coagulation. 

 In this view he differed from Mead. Dr. Brainard," so far as I am aware, was the 

 first to state that when the animal bitten dies soon, the blood is coagulable, and 

 that when death is delayed, it ceases to exhibit this condition. 



The statements of Dr. Brainard in regard to changes effected in the blood-disks 

 by Crotalus, or rather Crotalophorus venom, prepared me to find them more or less 

 altered in my own cases. He seems to have held an opinion, common enough at 

 the date of his paper,' namely, that woorara owed its potency to a serpent venom, 

 and that this poison as well as true venom seriously injured the blood-globules, and 

 produced a fatal result by causing their arrest in the capillaries. Fontana, who 

 examined the blood after death from viper bite, and who studied the mixture of 

 blood and venom, states that it prevented coagulation, but that he found the 

 globules unaltered. 



The general result of my own experiments on this subject may be very briefly 

 summed up. I have made very many careful examinations of the blood-disks of 

 frogs, birds, dogs, etc., which had been killed by snake bites. In a few rare cases 

 of prolonged secondary poisoning, I found a small proportion of the globules 

 altered and indented on the edge, but in no case were these changes very remark- 

 able. In primary or acute poisoning, I have never been able to detect the least 

 alteration in the blood-cells. It should be needless to add that I examined the 

 cells taken from the heart and from capillaries, and that these observations were 

 made so soon as death took place. 



I have also studied the effect on the disks of mixing the venom with blood, but 

 even in these circumstances no notable change took place in the blood-disks within 

 any brief period of time, as half an hour. Whether or not this direct contact 

 would affect them after a longer time, I cannot say, and it is a question which is 

 partially open for further study. 



» Fontana, vol. i. pp. 313 and 384. Skinner's Translation. 

 = Brainard, op. cit. 



3 Essay on a New Method of Treating Serpent Bites, et<;., by Daniel Brainard, M. D. CLicago, 1854, 

 pp. 14, and plates. 



