DIAGNOSTIC REACTIONS 299 



of complement (1 in 10) and 0.5 c.c. of antigen (1 in 10). At the 

 same time controls (tubes marked C) are prepared in which the 

 antigen is left out, so that 0.5 of each serum is combined with 0.5 c.c. 

 of complement and 0.5 c.c. of saline (in place of the antigen). The 

 E and C tubes properly marked with the patient's numbers are 

 placed in the water-bath for thirty minutes and then receive, each, 

 0.5 c.c. of the hemolytic amboceptor and 0.5 c.c. of the corpuscles. 

 They are then returned and left for thirty minutes longer, the tubes 

 being frequently shaken. After that some writers recommend that 

 they be placed on ice and examined the next morning. I can see 

 no advantage in this delay, and prefer to centrifugalize the tubes 

 and read them at once. Strictly speaking it is not necessary to wait 

 even thirty minutes if one places a tube containing antigen-comple- 

 ment-normal serum in the lot and breaks off the incubation as soon 

 as this control is completely hemolyzed. 



RESULTS. Complete inhibition or absolute fixation is, of course, 

 at once evident from the fact that the supernatant fluid (after centri- 

 fugation) is perfectly colorless, the corpuscles being all at the bottom. 

 Partial fixation will show itself by a more or less colored supernatant 

 fluid and the presence of a varying number of undissolved red cells 

 at the bottom, while with complete hemolysis there is no sediment 

 of red cells whatever. The results are accordingly noted as + ++, 

 ++, +, , and (see Plate VI). 



On the question of a well-marked fixation there can, of course, 

 be no dispute, but with slight fixations errors are very apt to 

 creep in. We would suggest that slight fixation be neglected and 

 reexaminations made, especially in cases which are submitted for 

 diagnosis. 



The controls will usually be found hemolyzed completely, but at 

 times, though rarely, sera are met with which fix more or less com- 

 pletely by themselves. In such cases it would, of course, not be 

 warrantable to say that the reaction in the E tube was due to 

 syphilis. What this independent inhibition means we do not know. 



Regarding the value of the Wassermann reaction, both from the 

 standpoint of diagnosis and in its bearing upon the question of 

 treatment, we would emphasize that its neglect in a doubtful case 

 from either point of view would constitute a grave Kunstfehler, 1 as 



1 An error of omission would approximately express the idea in our own 

 language. 



