196 VENOMS 



after a contact of two bours or more, 2 c.c. of distilled water be 

 added, coagulation is produced just as in saline plasma without 

 venom. 



B. — Effects of Venom upon the eed Coepuscles. 



(1) Hmmolysis. — The hsemolytic properties of venoms, that is 

 to say, their faculty of dissolving the red corpuscles, have been 

 the subject of very important researches on the part of a number 

 of investigators during the last few years (W. Stephens,^ Flexner 

 and Noguchi,^ Calmette,^ Phisalix,'' Preston Kyes and Hans Saohs," 

 Noc«). 



The different venoms are all hsemolytic, but in very variable 

 doses. It is possible to make a very precise comparative study of 

 them from this special point of view by taking as a base for each 

 venom, as was done by Noc, the unital dose of 1 milligramme 

 (or one-tenth of a cubic centimetre of a 1 per cent, solution freshly 

 prepared and not filtered, the filtration through porcelain retaining 

 an appreciable part of the active substance), and noting the time 

 strictly necessary for this dose of 1 milhgramme to dissolve com- 

 pletely, in vitro, 1 c.c. of a 5 per cent, dilution of red corpuscles of 

 the horse in physiological saline solution. 



It is very important, before allowing the venom to act on the 

 red corpuscles, to first wash the latter by means of several suc- 

 cessive centrifugings with 8 per 1,000 physiological saline solution. 



It is also better to choose the corpuscles of the horse in 

 preference to those of other species of animals, since they exhibit 



' Journal of Pathology and Bacteriologi/, 1899-1900. 



2 Journal of Exprrimenial Medicine, March 17, 1902 ; University of Penn- 

 sylvania Medical Bnllrtin, November, 1902. 



^ Comptes rendus dc I'Arademie des Scienrr.i, June 16, 1902. 



■* Comptes rendus de la Societe de Biologie, No. 27, 1902. 



' Berliner klinische Wochenschrift, Nos, 38, 39, 1902 ; Nos. 2-4, 1903 ; Nos. 

 42-43, 1903. 



'■ Avnalcs de VInstitut Pasteur, 1904, p. 387. 



