116 LABORATORY COURSE IN SERUM STUDY 



cholesterin is soluble whereas lecithin and certain allied lipoids 

 are insoluble in it). 



Extract 100 grams of mashed heart muscle with a liter of 

 absolute alcohol at 37 C. for several days. Filter and evaporate 

 to dryness with an electric fan. This usually takes 12 to 24 hours. 

 Dissolve the residue in ether (avoid flames). Stand the milky 

 ether solution in the ice box overnight and decant off the clear 

 supernatant portion. Evaporate this before an electric fan to a 

 small volume and to it add about 10 volumes of pure acetone. 

 Allow to stand for several hours and decant off the acetone. 

 Scrape the precipitate off with a spatula and preserve it under 

 acetone. For use dissolve about 0.3 grams of the brownish sticky 

 precipitate in 1 c.c. of ether and to it add 9 c.c. methyl alcohol. 

 The alcohol solution is fairly stable and can be used as a stock 

 solution. 



II 



TlTRATION OF WASSERMANN ANTIGEN 



Alcoholic extracts of organs contain substances which are 

 haemolytic and substances which have the power of binding com- 

 plement non-specifically, much as do bacterial suspensions and 

 extracts. They also contain substances which in combination 

 with syphilitic sera have the power of binding complement. 

 It is important to test for all three of these properties and a suit- 

 able extract must show an antigenic value (that is, the power to 

 bind complement in the presence of syphilitic serum) much higher 

 than its anticomplementary or haemolytic values. The haemolytic 

 power of the antigen seldom interferes practically, and is some- 

 what interfered with by the guinea pig and human serum used in 

 the test. 



Before standardizing the antigen, the alcoholic concentrated 

 antigen sliould be diluted 1-10 with salt solution, and the way in 

 which this suspension is made is of importance since the antigen 

 is in colloidal suspension and not in true solution and the anti- 

 complementary and antigenic value depend certainly in part on 

 the physical condition of the antigen. This will vary according 



