292 Wassermann Reaction for Diagnosis of Syphilis 



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 ob- 

 tainable 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 keptfor 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 belonging 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 compact 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 throughout 

 the newly added fluid. The tubes are next returned to the cen- 

 trifuge and again whirled until the corpuscles are sedimented, when 

 the fluid resulting from this first washing 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 

 undisturbed. Some prefer to give the corpuscles a third washing, 

 but it does not seem to be necessary. Of the remaining corpuscular 

 mass, 5 cc. are added to 95 cc. of salt solution to make a 5 per cent, 

 volume suspension, in which form they are ready for use. As the 

 corpuscles of healthy sheep thus treated form a practically invariable 

 unit, no titration or other preliminary is needed before they are used. 

 They must, however, be used within seventy-two hours to secure 

 satisfactory results, as they tend to soften when kept and so to lose 

 their standard value. If kept longer than twenty-four hours they 

 should be washed before using. 



(5) The Hemol3rtic Amboceptor. — As the validity of the test de- 

 pends upon the abihty or inabihty of the complement to dissolve 

 the corpuscles, and as this can only be achieved when appropriate 

 amboceptors are added, the hemolytic amboceptors must correspond 

 to the kind of blood-corpuscles employed in the experiment. As has 

 been shown, the greater number of investigators now employ sheep 

 corpuscles, hence must use such corpuscles as the antigen through 

 whose stimulation the amboceptors or antibodies are excited. 



The usual method of obtaining the amboceptor is in the blood- 

 serum of an experimentally manipulated rabbit. A large healthy 

 rabbit is employed for the purpose, and is given a series of intra- 

 peritoneal injections of the 5 per cent, suspension of washed and 



