The Hemolytic Amboceptor 299 



tive results, for in titrating the antigen we have developed the 

 reaction by which we can confirm the diagnosis of syphiUs in the 

 case from whom the syphihtic serum was obtained, and have failed 

 to develop it with the known normal serum. 



However, in order that those who perform the test may be able 

 to escape the numerous errors into which one may fall, it will be 

 necessary to point out the controls by which they can be avoided. 



A Wassermann reaction at the present time comprises not only 

 the test of the patient's serum, but simultaneously includes a long 

 series of other tests by which the validity of every part of the test 

 and the correct titer of all the reagents employed can be simultane- 

 ously 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, un- 

 necessary to make more than one series of controls. 



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

 cent, (physiologic salt solution, making each cubic centimeter of 

 the dilution of the fluid equal o.i cc. This quantity, carefully 

 measvured by the same volumetric pipette, is dropped into each 

 tube, and this pipette laid aside. 



The serum to be tested is drawn into a second finely graduated 

 pipette, and 0.2 cc. added to tubes i, 2, and 9, and that pipette 

 laid aside. 



The positive syphihtic serum used to control the test is similarly 

 drawn up in a fresh pipette and 0.2 cc. of it measured into tubes 

 3 and 4, and the pipette laid aside. 



The normal serum used as a control is similarly drawn into still 

 another pipette and 0.2 cc. measured into tubes 5 and 6, and the 

 pipette laid aside. 



The alcohoUc extract composing the antigen is next added, either 

 by diluting it so that i cc. contains the vmit, or measuring the unit 

 quantity directly into the tubes. The antigen is added to tubes 

 I) 3) Si and 7, and the pipette 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 cc. 



Each tube is now shaken carefully, so as not to cause frothing 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 suspension and, with 

 the exception of tube 9, receives one dose of amboceptor, either the 

 serum measured by diluting so that i cc. equals the dose, or the 

 necessary square of paper. This, in the former case, brings the total 



