On the Recognition of the Individual by Haimolytic Methods. 417 



It was thus found that the serum of almost all the immune cattle, in the 

 presence of a suitable complement, was highly hfemolytic, the hfemolytic 

 power naturally depending on the amount of blood which the animal had 

 received and on the date on which it was bled. 



The hfemolytic power of all the animals in the Institute was examined. 

 The sera of 76 out of a total of 101 were found to be capable of causing 

 the complete haemolysis of 1 c.c. of a 5 per cent, suspension of the 

 corpuscles of cattle imported from Cyprus, in one hour at 37° C, in as small 

 an amount as one-hundredth of a cubic centimetre in the presence of a 

 suitable amount of guinea-pig complement, and many sera hsemolysed at 

 much smaller doses. 



If the serum of one immune animal is tested on the corpuscles of a number 

 of individual animals of the same species, a great variation is seen in its 

 haemolytic action on the various corpuscles ; some being very highly 

 susceptible, others less so, and others almost unaffected.* 



If now the serum of a second immune animal is tested on the same series of 

 corpuscles, we get again differences in the action on the various corpuscles, 

 and again certain corpuscles are picked out as susceptible, while others are less- 

 affected. 



The two sera, however, do not necessarily pick out the corpuscles of the 

 same individuals, so that corpuscles which may be highly sensitive to one 

 serum may be almost unaffected by another. 



It is a curious fact that, so far as we have seen, the race of the animal 

 appears to be more or less immaterial and any influence exerted by this is. 

 quite masked by the individual characteristics. 



In no case was the serum of an immunised animal found to be haemolytic 

 for its own red blood corpuscles, so that we were dealing with an iso-, not an 

 auto-lysin. This result agrees with what Ehrlich and Morgenroth found in 

 the case of their goats. 



The complement of the ox, as occurring in the fresh immune serum, even 

 in the presence of a powerful hsemolytic isolysin, appears to be capable- 

 of effecting haemolysis of ox corpuscles only to a very slight extent or not 

 at all. 



If we imagine that the formation of these haemolytic isolysins in the ox i& 

 protective, and that it is an attempt on the part of the organism to effect th& 

 solution and removal of the red blood corpuscles which have been introduced 



* In this connection we have just seen a paper in the latest number of the * Muenchener 

 Medizinische Wochenschrift ' (April 5, 1910) by v. Dungern and Hirschfeld, who, working- 

 with agglutinins, have, by a somewhat similar method, shown that it is possible to divide- 

 up the animals of one species into classes, according to their agglutinating reactions. 



