332 Wassermann Reaction for Diagnosis of Syphilis 



every part of the test and the correct titer of all the reagents 

 employed can be simultaneously ascertained. Every one 

 who makes the test should practice some such systematic 

 method as is suggested by the following scheme for the " set- 

 up." Nine tubes are employed for the usual test. These are 

 stood in a rack in the same order for every test, and in the 

 course of time it becomes a matter of habit to know the tubes 

 by number, and to recall for what each stands. 



If many tests are to be made at one time, it is, of course, 

 unnecessary to make more than one series of the various con- 

 trols. 



Of the complementary serum we add i c.c. to 9 c.c. of 0.85 

 per cent, (physiologic) salt solution, making each cubic centi- 

 meter of the dilution of the fluid equal o.i c.c. This quan- 

 tity, carefully measured by the same volumetric pipet, is 

 dropped into each tube, and this pipet laid aside. 



The serum to be tested is drawn into a second finely gradu- 

 ated pipet, and 0.2 c.c. added to tubes i, 2, and 9, and that 

 pipet laid aside. 



The positive syphilitic serum used to control the test is 

 similarly drawn up in a fresh pipet and 0.2 c.c. of it measured 

 into tubes 3 and 4, and the pipet laid aside. 



The normal serum used as a control is similarly drawn into 

 still another pipet and 0.2 c.c. measured into tubes 5 and 6, 

 and the pipet laid aside. 



The alcoholic extract composing the antigen is next added, 

 either by diluting it so that i c.c. contains the unit, or measur- 

 ing the unit quantity directly into the tubes. The antigen is 

 added to tubes i, 3, 5, and 7, and the pipet laid aside. 



Lastly, each tube receives a correctly measured quantity 

 of 0.85 per cent, sodium chlorid solution to bring the total 

 bulk of fluid up to exactly 3 c.c. 



Each tube is now shaken carefully, so as not to cause froth- 

 ing of the fluid, and the rack is stood in a thermostat kept 

 at 37 C. 



At the end of an hour the rack is removed, and every tube 

 receives the addition of i unit of the sheep corpuscle sus- 

 pension and, with the exception of tube 9, receives one dose 

 of amboceptor, either the serum measured by diluting so that 

 i c.c. equals the dose, or the necessary square of paper. This, 

 in the former case, brings the total bulk of fluid to 5 c.c., in 

 the latter makes it necessary to add i more cubic centimeter 

 of salt solution to each tube. We aim to have exactly 5 c.c. 

 of fluid in each tube. 



