CONTRIBUTION TO THE STUDY OF THE EFFECT THE VENOM OF CROTALUS 

 ADAMANTEUS UPON THE BLOOD OF MAN AND ANIMALS. 



By S. Weir Mitchell, M. D., and Alonzo H. Stewart, M. D. 



THE ACTION OF FRESH CROTALUS VENOM UPON HUMAN BLOOD. 



These experiments were conducted with a view to determine the influence of the venom of 

 the Crotalw adamanteus upon the human blood corpuscles. It was thought that with the newer 

 methods of examining blood now in use additional knowledge of value could be obtained. 



Cases of poisoning by venom are so exceedingly rare in this country at the present time that 

 the only way to carry on this investigation was by noting the effect of the venom in various 

 dilutions upon the blood of man and of the lower animals and also by injecting subcutaneously 

 known quantities of venom into animals and then carefully studying their blood after it had 

 been influenced by the venom. 



In the study of the effect of the venom upon the shed blood of the animals the slides of blood 

 were sealed with balsam to protect the blood from the drying action of the air. Some of the 

 slides were kept at the temperature of the room; others containing the same mixture were placed 

 at body temperature in an incubator. All slides were watched carefully, at first on a warm stage, 

 then every few hours, to detect the changes that occurred from time to time. 



First, a control slide of normal blood was made and the characteristics of the corpuscles 

 noted. On a second slide the blood and the fresh venom were mixed in equal parts. Third, a 

 control slide of blood and normal saline solution was prepared; then slides on which were placed 

 blood mixed thoroughly with various strengths of venom in normal saline solution ranging from 

 10 to 0.01 per cent. 



Average normal human blood on carefully prepared slides at 37. 5° O. showed no marked 

 changes in forty eight hours. In seventy two hours the erythrocytes were crenated and the 

 ameboid motion of the leucocytes had entirely ceased. After one hundred and forty-four hours 

 had elapsed all the corpuscles were broken down. 



Blood and fresh venom, 20 cubic millimeters of each, were throughly mixed and preserved 

 from the atmosphere. The erythrocytes at once became globular, 3 to 5 micro-millimeters in 

 diameter, and more highly refractive. The color changed from a slight greenish yellow to a light 

 chocolate tinge, and in many of the slides the corpuscles became quite adherent, sticking together 

 in large clumps or drawn out in long stringy masses. These strings of corpuscles often show the 

 erythrocytes drawn out to 20 micro-millimeters in length. The tendency of the corpuscles to form 

 rouleaux seemed to have entirely disappeared. The leucocytes were reduced from 18 and 20 micro- 

 millimeters to 10 and 12 micro-millimeters in diameter, and they became more refractive at the 

 borders. The ameboid movement ceased at once. Examination in twenty-four hours showed the 

 erythrocytes to be losing color, the long strings having disappeared. The aggregation in clumps 

 was still marked, except where the layers of corpuscles were very thin. Here the formation of 

 small oblong crystals from the blood corpuscles began to be visible. At first the corpuscle 

 became square, and then several faint light lines parallel to each other appeared on the surface. 



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