SECTION A. ON THE PROPERTIES OP IMMUNE- 

 BODIES. 



THE SPECIFICITY OF IMMUNE-BODIES 



This subject is part of the question regarding specificity 

 of anti-substances in general, and the results of investi- 

 gation correspond with the facts established in the case of 

 precipitins, agglutinins, &c. A hsemolytic serum is always 

 most active towards the corpuscles used in its develop- 

 ment, but it may also have some action on the blood 

 of allied species. To give a concrete example : an anti-ox 

 hsemolytic serum with a hsemolytic dose of -0005 c.c. when 

 reactivated with guinea-pig's complement, was found to 

 produce lysis of sheep's corpuscles in a dose of 0012 c.c. 

 When a small quantity of this serum, however, was treated 

 with excess of sheep's corpuscles, time being allowed for 

 combination, and then the corpuscles were centrifugalized, 

 it was found that the serum had lost its hsemolytic action 

 on sheep's corpuscles, the immune-body having been 

 removed by the previous contact. It still, however, pos- 

 sessed marked hsemolytic action on ox corpuscles, the 

 hsemolytic dose being -0012 c.c. ; that is, the immune-body 

 had been reduced to a little less than half of the original 

 amount. In this instance it therefore appears that about 

 half of the immune-body molecules act equally on sheep 

 and ox corpuscles, whilst the other half act only on ox 

 corpuscles. Or, in other words, half of the hsemolytic 

 receptors of the ox corpuscles are similar (so far as com- 

 bining affinities are concerned) to those in the sheep, whilst 

 the others are different. Ehrlich and Morgenroth l worked 

 out this subject very completely in the case of the corpuscles 

 of the ox and of the goat, the results obtained being similar 

 1 Ehrlich and Morgenroth, Berlin. Klin. Woch., 1901, nos. 21, 22. 



