476 THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 



cent. The Noguchi test, on the other hand, may be conducted with 

 inactivated serums, when the danger of false reactions is removed, 

 but the delicacy of the test is likewise diminished, so that it more 

 closely approaches the Wassermann reaction. 



Noguchi endeavored to simplify the technic of the syphilis reaction 

 by preparing complement, antigen, and amboceptor dried on filter- 

 paper. These were titrated and so adjusted that a certain measure 

 of paper represented the required amount of each reagent. In this 

 manner it would be possible for a large central laboratory to prepare 

 and standardize these reagents, putting them up ready for use in the 

 simplest possible form, and thus making them available for the 

 practising physician. Complement, however, deteriorates so rapidly 

 that the paper is useless unless it is freshly prepared. The antigen 

 slips likewise deteriorate, but not so rapidly as the complement; the 

 amboceptor, however, is well preserved by this method, and forms 

 a simple method for titrating and handling this important reagent. 



Technic of the Noguchi Modification. (1) Complement is fur- 

 nished by the fresh, clear serum of the guinea-pig, put up in 40 per 

 cent, solution, prepared by diluting 1 part of serum with 1J^ parts of 

 normal salt solution. Dose 0.1 c.c. (5 drops from a capillary pipet). 

 Whenever possible it is always best to use a mixture of the serums 

 from two or more guinea-pigs. 



2. Human Corpuscles. These are washed three times with normal 

 salt solution, and used in dose of 1 c.c. of a 1 per cent, suspension. 

 To a graduated centrifuge tube containing 9 c.c. of sterile 2 per cent, 

 sodium citrate in normal salt solution add 1 c.c. of blood and shake 

 gently. This amount of blood is easily secured by pricking the finger 

 with a lancet and collecting the blood in the centrifuge tube up to the 

 mark 10. This is centrifuged thoroughly, and the supernatant fluid 

 drawn off. More saline solution is then added to the corpuscles stirred 

 up and the mixture centrifuged. The washing is repeated once more, 

 and the supernatant fluid discarded. The corpuscles are then sus- 

 pended in sufficient salt solution to make a total volume of 100 c.c. 



3. Hemolytic Amboceptor. Antihuman hemolysin is prepared by 

 immunizing rabbits with human cells, as described on p. 72. It is a 

 difficult matter to secure a potent amboceptor; human erythrocytes 

 are more toxic than sheep's cells for rabbits, and most animals produce 

 but small amounts of the amboceptor. Hemagglutinins are produced inV 

 large amounts, and when using a low titer hemolytic serum, the test- 

 corpuscles are quickly agglutinated in small dense masses that are 



