95 



lone without control by the original 

 IFASSERMANN process. 



SACHS and GEOPxGI recently des- 

 cribed a process of flocculation which 

 in my opinion, is the best hitherto 

 known, and may substitute the WASSER- 

 MANX test, if all tlie component ele- 

 ments are perfectly known and tilrated. 

 The technic is much simpler and the 

 results, when compared with tliose of 

 the WASSERMANN test, agree very 

 well as shown hj all the statistics pub- 

 lished up to now. 



I shall now proceed to give a more 

 detailed description of the preparation 

 of the reactives and of the technic: 



Antigen. The antigen used in the 

 SACHS-GEORGI lest is bullock heart. 

 This should be fresh aiul only the miis- 

 cular tissue used, cut into small fra- 

 gments and triturated in a mortar mitil 

 it becomes a homogeneous pulp; with 

 this an emulsion is made in absohUe 

 alcohol, in lhe proportion of 1 gramme 

 lo 5 cc. II is placed, together with glass 

 beads, in a vial, sealed with paraffin 

 and kept in the incubator for a fort- 

 night during which period it has lo be 

 shaken twice daily. Finally it is filte- 

 red through filler paper and tlie e\li;nl 

 is ready. 



In practice Ibc use of only one ex- 

 tract should be avoided, just as one 

 ought not to use one anligen alone in 

 the WASSERMANN lest; it is safer to 

 employ three perfectly titrated and con- 

 trolled extracts. They may be prepared 

 from different fresh bullock hearts or 

 l)y mixing pieces of various hearts 

 always using the same method. 



The antigen thus obtained coiislilu- 

 les the concentrated solution; for use 

 as a reactive it musl be diluted with 

 two parts of absolute alcohol, adding 

 cholesterin and finally diluting with phy- 

 siological solution in the proportion of 

 1 lo 6. The dilution must be made only 

 ^vhen the anligen is about to be used. 



The concentraled solulion should be kept 

 well shut in a cool and dark place. 



The antigen used in the SAGHS lest 

 contains much cholesterin but its pro- 

 poi'tion varies, as neither the antigenic 

 value of the extract nor of the choles- 

 terin are constant. Hence it is necessary 

 to ascertain the optimum of cholesterin 

 to be added to a certain volume of con- 

 centrated solulion of antigen after dilu- 

 ting in two parts of absolute alcohol. 

 For this purpose a titration has to be 

 made, so as to ascertain the quantity of 

 cholesterin, wliich, added to the antigen, 

 will cause it lo produce flocculation of 

 a known positive serum and will leave 

 a known negative one unaltered. 



l"or this purpose a centesimal solu- 

 tion of cholesterin should be prepared 

 and kept in a sealed vial. 



Titration of antigen. 



l"or lilraliou the following is re- 

 quired : 



1.— Concentrated antigen solulion. 



2.— Absolule alcohol. 



3.— l"o alcoliolic solulion of choles- 

 terin. 



1. — Known jjositive sera. 



."). — Known negative sera. 



A scries of 10 lest tubes is then pla- 

 ced at hand and Ice. of the concentrated 

 solution of anligen and 2 cc. of absolule 

 alcohol are mixed in each tube. The al- 

 coholic cholesterin solulion is then ad- 

 ded, beginning with 0,1 cc. and gra- 

 dually increasing up to 1 cc. in the 

 last lul)e. Ten solutions of antigen with 

 augmenting doses of cholesterin are thus 

 obtained. Each tube now contains a dif- 

 ferent anligen, lo be tried with posi- 

 tive and negative sera. 



Now we take a new series of ten 

 test lubes in which we dilute each anti- 

 gen in physiologic solulion at 0,85 o'o in 

 the proportion of 1 to 5. For this pur- 

 pose 1 cc. of antigen is mixed with 

 1 cc. of physiologic solulion, is well 



