194 STUDIES IN IMMUNITY. 



In brief, then, red blood corpuscles owe their characteristic 

 absorbing properties to their stromata. Is the property in rabbit 

 corpuscles of producing a hemolytic power when injected in guinea- 

 pigs also due to their stromata? To answer this question stromata 

 that have been freed from all soluble substances by carefully wash- 

 ing in salt solution are obtained and injected into guinea-pigs. 

 Each guinea-pig receives the stromata from 4 to 5 c.c. of defibri- 

 nated blood. Corresponding guinea-pigs are injected with a lim- 

 pid reddish fluid containing the soluble substances obtained from 

 corpuscles by treating them with distilled water and subsequently 

 adding salt. This fluid is then centrifugalized to deprive it of sus- 

 pended stromata. After injection lasting for three weeks it is found 

 that guinea-pigs injected with stromata furnish an active hemolytic 

 serum; those that receive the limpid fluid containing hemoglobin 

 have a serum like that of normal guinea-pigs. 



Corpuscles fix the active substances of hemolytic serum. Can 

 the nature of this phenomenon of fixation be more exactly deter- 

 mined? Is it a question of true chemical combination by the union 

 of certain elements of the red blood cells with the active principles, 

 and does it take place according to fixed proportions? Or should 

 we consider the fixation by corpuscles as more like a dyeing phe- 

 nomenon? A substance to be dyed, as we know, absorbs extremely 

 varying amounts of the dye, so as to take shades of varying inten- 

 sity. The amount of dye that is fixed is subject to wide variations; 

 chemical reactions, properly speaking, on the other hand, are 

 characterized by a reaction in definite proportions. 



We shall not consider this difficult problem fully, as we have not 

 as yet sufficient data, but a single experiment may be given which 

 may prove important in future studies of this subject. 



A small amount of defibrinated rabbit blood (for example, 0.1 

 of a cubic centimeter) is added to a certain amount of fresh hemo- 

 lytic serum (for example, 0.4 of a cubic centimeter). The corpuscles 

 are rapidly destroyed. The hemolysis although still rapid is some- 

 what slower if a large dose of blood is added (say 0.3 or 0.4 of a 

 cubic centimeter). The destruction of corpuscles naturally enough 

 varies in rapidity with the amount of blood added to the hemotoxin. 

 And yet the serum that is used can destroy completely and relatively 



