APPENDIX. 



153 



the supernatant fluid poured off and centrifuged so 

 as to be perfectly clear.* 



The serum for the test is collected from the 

 patient in the usual way by drawing from 5 to 

 10 cc. of blood from a vein at the elbow, placing 

 the blood in a sterile test tube and allowing it to 

 clot. Cerebrospinal fluid, obtained by lumbar 

 puncture, is preserved with 0.5% carbolic acid, and 

 then strongly centrifuged so as to make it perfectly 

 clear. 



The sheep blood cells are obtained by defibrinat- 

 ing sheep blood, centrifuging and washing the blood 

 cells repeatedly with normal salt solution to remove 

 traces of adherent serum. A 5% suspension in salt 

 solution is used. 



The hasmolytic antibody consists of the serum of 

 a highly immunized (against sheep blood cells) 

 rabbit, the serum being inactivated by heating to 

 56 C. In the tests cited by Wassermann, one cc. 

 of a 1/1500 dilution of serum dissolved one cc. of 

 5% suspension of sheep blood cells at 37 C. in 

 two hours. 



The complement consists of freshly drawn guinea- 

 pig serum. The test is carried out as follows : 



To constant quantities of spinal fluid (e.g. i cc. 

 of the i/io dilution) decreasing amounts of the 

 extract of organs are added, thus 0.2, o.i, 0.05 cc. 

 Then i cc. of a i/io dilution of fresh normal guinea- 



* In a very recent article, Wassermann states that more uni- 

 formly active extracts can be obtained by using 96% alcohol in 

 place of the water in the above formula. 



