352 STUDIES IN IMMUNITY. 



antihemolytic property, and the treated serum itself acts only to 

 protect the species of corpuscles with which this serum has been 

 digested. The explanation which Sachs offers for the facts up to 

 the present point is as follows. Normal rabbit serum contains 

 a series of normal hemolytic amboceptors, of which some are specific 

 for sheep corpuscles. When treated with sheep corpuscles rabbit 

 serum loses its sheep amboceptors, but the remaining amboceptors 

 (active against other corpuscles), although unattached to their 

 specific cells, have a greater affinity for complements than do the 

 sheep corpuscles sensitized with serum rabbit > ox, added as a 

 test for alexin; and hemolysis of these test corpuscles does not take 

 place.* 



If we repeat in detail Sachs' first experiment, together with a 

 control suggested by the facts I have already adduced, it is evident 

 that his explanation of this interesting phenomenon is certainly 

 incorrect. I have worked with sheep blood only and have em- 

 ployed the specific serum used by Sachs, that is, the serum of a 

 rabbit immunized against ox blood (which, of course, readily destroys 

 ox red blood corpuscles, but also works satisfactorily against the red 

 cells of the sheep). 



EXPERIMENT IV. 

 Three tubes are prepared as follows: 



Tube A. Sheep corpuscles (the sediment of blood washed once 



in 15 volumes of NaCl solution of 0.85 per cent 1.5 c.c. 



Normal rabbit serum, 55 degrees 1.5 c.c. 



Tube B. Normal rabbit serum, 55 degrees 1.5 c.c. 

 Tube C. Sheep corpuscles (the sediment of blood washed five 



successive times with fresh volumes of NaCl) 1.5 c.c.* 



Normal rabbit serum, 55 degrees 1.5 c.c. 



Of these tubes, A and B correspond exactly in dosage to those 

 given by the German author. Just how completely he washed 



* As is usual with the Ehrlich school, an hypothesis was invented in harmony 

 with the lateral-chain theory, to explain the Neisser-Wechsberg phenomenon; 

 and it is this hypothesis and not fundamental experimental facts which is used 

 as a foundation for further hypotheses. It has never been proved that an alexin 

 can unite with an immune body unless the latter has formed a complex with the 

 cell or substance, the injection of which has given rise to the specific serum. The 

 Neisser-Wechsberg phenomenon, which has been accepted by the Ehrlich school 

 as proving this union, is, in reality, unquestionably due to another cause, as I 

 shall consider later. 



