COMPLEMENT FIXATION IN GONOCOCCUS INFECTIONS 505 



chapter, with the technic ef the syphilis reaction, or one-tenth the quan- 

 tity employed in the original Wassermann technic may be employed. 

 I prefer to employ the larger amounts because the readings are usually 

 easier to interpret. 



Fresh guinea-pig complement serum is diluted 1 : 20 and used in dose 

 of 1 c.c. ( = 0.05 c.c. serum); sheep's corpuscles are made up in a 2}^ per 

 cent, suspension and used in dose of 1 c.c.; antisheep amboceptor is 

 titrated (see p. 399) and used in an amount equal to 2 hemolytic doses 

 in conducting the antigen titration and in the test proper. 



Kolmer and Brown 1 have compared the practical value of the anti- 

 sheep and antihuman hemolytic systems in the examination of a number 

 of serums. When the latter were used, some of the reactions were 

 somewhat stronger and yielded slightly better results, showing the 

 influence, probably, of natural antisheep amboceptor present in a large 

 proportion of human serums. 



Antigen. This constitutes the most important ingredient of the 

 test. As Teague and Torrey and Schwartz and McNeal have em- 

 phasized, the antigen should be prepared of many different strains of 

 gonococci. The difficulty of isolating this organism and the constant 

 care required in subculturing and keeping a large number of strains alive 

 render it practically impossible for many persons to prepare a gonococcus 

 antigen. Therefore until simpler methods are devised, this antigen is 

 best prepared in large central laboratories, where the cultures are handled 

 and preserved by specially trained persons. 



The gonococci are well grown on a salt-free veal agar, neutral in 

 reaction to phenolphthalein, and to which a few drops of sterile hydrocele 

 fluid may be added. After culturing for from twenty-four to forty- 

 eight hours the growths are washed off with distilled water, and the 

 emulsion is heated in a water-bath for two hours at 56 C. It is then 

 heated at 80 C. for one hour, filtered through paper pulp or centrifu- 

 galized, and passed through a Berkefeld filter which is reserved for this 

 purpose alone and is neutral in reaction (see page 78) . A small amount 

 of preservative, as, e. g., 0.1 c.c. of a 1 : 100 dilution of phenol to each 

 cubic centimeter of antigen, may be added. The antigen is then well 

 preserved in small amounts in ampules that are sealed and heated to 

 56 C. for half an hour on three successive days. Just before being 

 used the antigen is made isotonic by adding 1 part of a 10 per cent, salt 

 solution to 9 parts of antigen. I preserve the antigen in ampules con- 

 taining 1 c.c., and after removing the antigen from the ampule to a large 

 test-tube, add 1 c.c. of 10 per cent, salt solution, and dilute the whole 

 1 Jour. Infect. Dis., 1914, 15, 6. 



