322 Wassermann Reaction for Diagnosis of Syphilis 



four hours. Longer it should not be kept or used, as it begins 

 to deteriorate almost at once, and the deterioration increases 

 in rapidity in proportion to the length of time it is kept. The 

 quantity of the complement in the serum of the guinea-pig 

 is fairly constant, when the animal is regularly fed, and fur- 

 nishes a fairly uniform reagent that requires no titration. 



II. For the second, or hemolytic, test two additional re- 

 agents are required: 



Blood-corpuscles to be dissolved. 



Hemolytic amboceptors by which complement may be 

 united to them. 



(4) The Blood-corpuscles. It makes no difference what 

 kind of blood-corpuscles are employed. Ehrlich and Mor- 

 genroth, in their pioneer experiments into the mechanism of 

 hemolysis, used goat corpuscles. Bordet used rabbit cor- 

 puscles; Wassermann, Neisser, and Bruck, sheep corpuscles; 

 Detre, horse corpuscles; Noguchi, human corpuscles. 



As those who do many tests require a considerable quantity 

 of blood, it seems wisest to make use of some kind that is 

 readily obtainable in any quantity, hence most investigators 

 now follow Wassermann and his collaborators and use sheep 

 blood, which is easily obtained at a slaughter-house or from 

 sheep kept for the purpose. 



The flowing blood is caught in some open receptacle, stirred 

 until it is defibrinated (it must not be permitted to coagulate), 

 and then taken to the laboratory. 



The corpuscles must next be washed with care, so as to 

 free them from all traces of amboceptors and complement be- 

 longing to the serum in which they are contained. For this 

 purpose a centrifuge is indispensable. The tubes of the 

 apparatus are filled with the defibrinated blood and then 

 whirled for fifteen minutes until the corpuscles form a com- 

 pact mass below a fairly clear serum. The serum is then 

 cautiously removed and replaced by 0.85 per cent, sodium 

 chlorid solution, the top of each tube closed by the thumb, and 

 vigorously shaken so as to distribute the corpuscles through- 

 out the newly added fluid. The tubes are next returned to 

 the centrifuge and again whirled until the corpuscles are 

 sedimented, when the fluid resulting from this first wash- 

 ing is removed and replaced by fresh salt solution, in which 

 the corpuscles are again thoroughly shaken up. They are 

 now again whirled until again sedimented, when the second 

 washing is removed, leaving the corpuscular mass undis- 



