REACTIONS DEPENDING UPON COMPLEMENT FIXATION 279 



each, 0.5 c.c. of the hemloytic 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-complement-norraa/ 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. 

 I, for one, would suggest that slight fixation be neglected and re-exami- 

 nations made, especially in cases which are submitted for diagnosis. 



The controls will usually be found hemolyzed completely, but at 

 times sera are met with which fix more or less completely by them- 

 selves. 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, I would emphasize that its neglect in a doubtful case 

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

 the Germans put it, of which, very fortunately, but few modern 

 physicians are apt to be guilty. 



Considered from the diagnostic standpoint a well pronounced 

 positive reaction may probably always be regarded as indicating the 

 existence of syphilis, if we can rule out such diseases as frambesia, 

 leprosy, sleeping sickness, and scarlatina. In malignant disease 

 a certain degree of complement fixation may also be obtained, in 

 a considerable number of cases, but I have not been able to convince 



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

 language. 



