THE WASSERMANN REACTION 505 



amounts of the hsemolytic amboceptor. In this way the haemolytic 

 amboceptor is standardised and the manner of carrying out these 

 two tests is illustrated by the Tables (A and B) on p. 504. 



(d) Fluid to be tested. Either the blood-serum or the cerebro- 

 spinal fluid is used in the test. If the test is carried out in small 

 test tubes, then 5 c.c.-lO c.c. of blood must be withdrawn from a 

 superficial vein with a sterile 10 c.c. syringe. If, however, the test 

 is carried out in small quill -tubes (which the writer believes is quite 

 as efficient as with larger tubes), then only 1 c.c. or 2 c.c. of blood 

 or less are needed (a Wright's capsule-full will suffice), and this may 

 be obtained from the ear or by binding some small rubber tubing 

 round the thumb and puncturing the soft tissues at the side near 

 the nail : when bleeding ceases, the rubber ligature should be 

 removed and re -applied, and this may be repeated two or three 

 times. The blood should be collected in a sterile tube and allowed 

 to coagulate ; this may be hastened if necessary by placing the 

 tube of blood in the warm incubator for half an hour and centri- 

 fuging. After the serum is separated, it is pipetted into another 

 tube, which is then heated in a water- bath to 56 C. for half an 

 hour immediately before testing in order to destroy its content of 

 complement. The latter procedure is important as a proportion 

 of sera from diseases other than syphilis may react positively if 

 un heated. 



In certain nervous diseases, e.g. general paralysis and tabes, it 

 may be necessary to test the cere bro -spinal fluid, which may react 

 positively when the serum is negative. The fluid is obtained by 

 lumbar puncture. An amount rather larger than the serum is 

 required ; it should be free from blood and cellular elements (which 

 may be removed by centrifuging if necessary) and it should not be 

 heated. 



THE TEST. Tubes about 3 in. by -^ in. diameter are used when 

 the " large quantity " method is carried out and the necessary 

 quantities of the reagents are measured with 1 c.c. pipettes divided 

 into hundredths. In the " small quantity " method tubes about 

 1| in. by i in. internal diameter are used, and the necessary quan- 

 tities are measured with a Wright's pipette furnished with a rubber 

 teat and having a volume or unit marked with a grease -pencil 

 about f in. from the point, and also a four -unit mark higher up. 

 Dilutions are made with 0-85 per cent, saline solution, and in all 

 cases the same total volume should be maintained in all the tubes. 

 The " small quantity " method may be now described ; if the 

 " large quantity " method is adopted the principle is precisely 

 similar but larger volumes of the reagents are used. For the 



