METHODS FOR CONDUCTING THE SYPHILIS REACTION 469 



control receives 1 c.c. of the suspension and 3 c.c. of salt solution, and 

 the tube is plugged with cotton to show that it is finished. 



All tubes are shaken gently and incubated for one hour at 37 C., 

 at the end of which time 2 units of amboceptor and 1 c.c. of the cor- 

 puscle suspension are added to all except the corpuscle control. Each 

 tube is shaken and all are reincubated for an hour or an hour and a half, 

 the length of time depending upon the hemolysis of the serum controls 

 when the readings are made. 



Reading the Results. As is usual, the controls are examined first. 

 The hemolytic, antigen, negative serum, and all serum controls should 

 be completely hemolyzed. The corpuscle control should show no 

 hemolysis, indicating that the salt solution was isotonic and the cor- 

 puscles free from undue fragility. 



A 1 per cent, hemoglobin solution in distilled water is prepared by 

 mixing 1 c.c. of the washed corpuscles used in preparing the suspension 

 with 99 c.c. of distilled water. Into a series of tubes dilutions of 

 this solution are placed as follows : 



Tube 1 : 10.0 c.c. of hemoglobin solution = 100 



Tube 2: 9.0 c.c. " " " 1.0 c.c. distilled water =90 



Tube 3: 8.0 c.c. " " " 2.0 c.c. " " =80 



Tube 4: 7.0 c.c. " " " 3.0 c.c. " " =70 



Tube 5: 6.0 c.c. " " " 4.0 c.c. " " =60 



Tube 6: 5.0 c.c. " " " 5.0 c.c. " " =50 



Tube 7: 4.0 c.c. " . " " 6.0 c.c. " " =40 



Tube 8: 3.0 c.c. " " " 7.0 c.c. " " = 30 



Tube 9: 2.0 c.c. " " " 8.0 c.c. " " =20 



Tube 10: 1.0 c.c. " " " 9.0 c.c. " " = 10 



Tube 11: 0.4 c.c. " " " 9.6 c.c. '' " =4 



Tube 12: 10.0 c.c. = 



This scale is not permanent, and must be prepared anew for each 

 set of reactions. 



A negative reaction is indicated in the seventh tube, which contains 

 the maximum dose of serum (0.2 c.c.), by complete hemolysis or by 

 hemolysis ranging from 80 to 100, according to the scale. Inhibition 

 of hemolysis in this tube giving a hemoglobin scale ranging from 70 

 to 4 (inclusive) is regarded as a positive reaction. Absolute lack of 

 hemolysis in this tube is according to the scale, but usually the 

 patient's serum or complement serum is sufficiently tinged with hemo- 

 globin to give a slight color to the supernatant fluid, so that an Ab- 

 solute positive reaction may range from to 4. For instance, the 

 serum of an untreated case of secondary syphilis gave the following 

 reading (see Fig. 117). 



