42 COLLECTED STUDIES IN IMMUNITY. 



able, however, is the fact that the body cells of the same animal 

 are able to produce this phenomenon. 



Exact quantitative examinations showed that there were dis- 

 tinct differences. The spleen and kidney of a rat, for example, were 

 more strongly active than the same organs of a guinea-pig, while 

 the liver tissue of the two species possessed equal activity; the 

 spleen and kidney of the rat abstracted more complement from 

 rabbit serum than did the same quantity of liver tissue, whereas 

 in the guinea-pig the liver acted more strongly than the spleen, and 

 the latter, again, more strongly than the kidney. Virulent cholera 

 vibrios acted only one-quarter as strongly as the completely avirulent 

 " cholera Calcutta." (The number of active individuals could not, 

 of course, be regarded.) Yeast cells were weakly active, anthrax 

 bacilli strongly so. In the case of anthrax bacilli I tested the action 

 of heat on this property to abstract complement from rabbit serum, 

 and found that it is not destroyed by heating the bacilli for twenty 

 minutes to 56 C., but that it is destroyed by heating them for only 

 a short time to 98 C. But the property of the cells to abstract 

 complement from rabbit serum is lost not only through the action 

 of heat, but also when the particular cells previous to their mixture 

 with rabbit serum have been allowed to remain in contact with another 

 serum. For example, 1 grm. finely crushed kidney tissue of cattle 

 is mixed with 2 cc. cattle serum, allowed to act at 37 C. for half an 

 hour and then separated from the serum by centrifuge. If 2 cc. 

 rabbit serum are now added to the sediment, and this is allowed 

 to stand for half an hour at 37, it will be found on testing with cattle 

 blood immune body that there is no diminution of complement 

 content; but such a diminution does occur when, with exactly the 

 same procedure, 8 p. m. NaCl solution is used in place of the cattle 

 serum. 



These phenomena are best explained by assuming that the cells 

 in question, in contrast to the erythrocytes, possess groups which 

 have a very close chemical relation to those of the complement which 

 reactivates the cattle blood immune body. The affinity of the cells 

 may, in fact, be greater for the complement than for any immune 

 body directed against other cells of the same animal species. For 

 example, if we add ciliated epithelial cells from the trachea of cattle 

 to an immune serum derived from a rabbit by treatment with cattle 

 blood, we shall under favorable circumstances find that the immune 

 body has been partially, but the complement completely, abstracted 



