166 ANTIGENS AND THE TECH NIC OF SERUM REACTIONS 
7. The serum to be tested^ inactivate, use 0.2 cc.^ 
Unknown serum. 
Known positive 
syphilitic serum. 
Known normal 
non-syphilitic serum . 
Tube 1. 
Tube 3. 
Serum, 0.2 cc. \ Serum, 0.2 cc. 
Complement, 0.1 cc. Complement, 0.1 cc. 
Salt solution, 2.7 cc. , Salt solution, 2.7 cc. 
Tube 5. 
Serum, 0.2 cc. 
Complement, 0.1 cc. 
Salt solution, 2.7 cc. 
Tube 7. 
Complement, 0.1 cc. 
Salt solution, 2.9 cc. 
Tube 2. 
Serum, 0.2 cc. 
Complement, 0.1 cc. 
Antigen,' 1 cc. 
Salt solution, 1.7 cc. 
Tube 4. 
Serum, 0.2 cc. 
Complement, 0.1 cc. 
Antigen, 1 cc. 
Salt solution, 1.7 cc. 
Tube 6. Tube 8. 
Serum, 0.2 cc. 
Complement, 0.1 cc. [ Complement, 0.1 cc. 
Antigen, 1 cc. Antigen, 1 cc. 
Salt solution, 1.7 cc. Salt solution, 1.9 cc. 
1 
After mixing, the tubes are placed in a water-bath maintained at 
37° C. for one hour, to permit of the fixation of complement; 1 cc. 
of a 5 per cent suspension of erythrocytes and 2 units of hemolysin 
are then added to each tube, mixed and reincubated for one hour, 
then read. Tubes 1, 3, 5, 7, 6 and 8 should show complete hemolysis. 
Tube 4 should show complete inhibition of hemolysis (positive reac- 
tion). If such be the case all the reagents are properly adjusted, and 
Tube 2, containing the unknown serum, is read. If hemolysis is 
absent the reaction is positive; if hemolysis is complete the reaction 
is negative.^ 
The Method of Nocjiichi.^—k rigorous standardization of reagents is 
a prerequisite for accuracy in the serum diagnosis of syphilis, and 
Noguchi has pointed out that a variable inherent inaccuracy exists 
in the Wassermann method. He has shown that human sera may 
contain variable amounts of hemolysin specific for sheep erythro- 
cytes. Human sera, however, contain no hemolysin for human 
erythrocytes. The Noguchi modification, therefore, substitutes human 
red blood cells (obtained from fresh placenta or at very recent autop- 
sies) for sheep red blood cells. Rabbits are immunized to carefully 
washed human erythrocytes and the hemolytic unit of the rabbit 
1 According to Blumenthal and Wile (Berlin, klin. Wchnschr., 1908, 45, 1050) the urine 
of syphilitics frequently gives a strongly positive reaction. Simon (Bull. d. Acad, de 
Medecine, 1920, 80, iii, 73) found in 166 syphilitics that the blood and urine were parallel 
in 53 per cent of tests: positive in blood and negative in urine, 62 cases; positive in 
urine and negative in blood, 15 cases. Positive urines were obtained more commonly 
from older cases; recent infections were more frequently negative in urinary tests. 
'^ This must be shown not to be anticomplementary. 
' Twice the antigenic titer, determined by titration, diluted with salt solution ; thus, if 
the antigenic titer of the acetone insoluble extract is 0.2 cc, and the anticomplementary 
titer is found to be 1.75 cc, 0.4 cc. of the extract are diluted with 0.6 cc. salt solution 
and used in the diluted state. In practice, enough extract should be diluted to last one 
day. 
^ For a discussion of results, see section on Treponema pallidum. 
* Noguchi: Serum Diagnosis of Syphilis. 
