SYPHILIS gg 



emulsions of fatty substances, the complement will disappear, 

 whereas if serum from a non-syphilitic person is treated in the 

 same way it will not. 



The emulsion of fatty substances is usually but incorrectly 

 termed the " antigen." It is prepared in several ways,' but the 

 following will be found satisfactory : Take human heart or liver 

 from the post-mortem room, or sheep's heart or liver ; mince them 

 finely (freeing it from fat or fibrous tissue in the case of the 

 heart), and to each gramme of material add 3 c.c. of absolute 

 alcohol. Shake thoroughly, and let the mixture stand twenty- 

 four hours, shaking occasionally. Then heat in a water-bath at 

 60° C. for one hour (this is not really essential), and again shake 

 thoroughly. Allow to settle, and dilutfe the clear supernatant 

 fluid when required for use in the following way : Take 

 9 volumes of normal saline solution, measuring them out by 

 means of a pipette, and place them in a small test-tube. Now 

 take I volume of the alcoholic antigen, and float it on the surface 

 of the saline solution. You will see a turbid zone (due to the 

 precipitation of liquid substances dissolved in the alcohol) at the 

 zone of contact. After five minutes or so give it a very slight 

 shake, so as partially to mix the fluids together. After another 

 interval repeat the process, and ultimately stir them together. 

 It is advisable that the fluids should always be mixed for use in 

 this way.* 



In actual practice the alcoholic solution of antigen requires 

 careful testing and standardizing, but this is hardly necessary for 

 the present, and will be described later. 



Experiment i. — Mix together i volume of fresh serum from a 

 normal (or non- syphilitic) person, and 4 volumes of the antigen 

 diluted as above, and incubate for ten minutes in the ordinary 

 incubator, or five minutes in a water-bath at 37° C. 



Now add i volume of serum from an immunized rabbit, heated, 

 and I unit of the emulsion of the human red corpuscles. 



Result. — The corpuscles will be dissolved. 



Explanation. — This is a negative Wassermann reaction. The 

 complement does not disappear in presence of this emulsion of 

 lipoid substances in normal saline solution. 



* A much better antigen is prepared by making a i in 10 extract of heart- 

 muscle in alcohol, and adding to it a i per cent, solution of cholesterin in 

 alcohol in the proportions of 5 : 4. Mix rapidly with saline, in proportions 

 which must be determined by experiment. 



