BY R. GREIG SMITH. 295 



destroyed by an exposure for 3 minutes at 60° and for 60 minutes 

 at 55°. The experiments were chiefly made upon staphylococci, 

 but other bacteria responded to the action, showing that in all 

 probability the opsonins exercise their power upon all bacteria. 

 The opsonin is supposed to fix itself upon the bacterium and so 

 prepare or render it fit for absorption by the phagocytes. When 

 so fixed, the opsonin is not destroyed by exposure to temperatures 

 for times that would destroy the free body, such as 60° for 5 

 hours. 



It is obvious that before testing the influence of agglutination 

 upon phagocytosis, it would be necessary to destroy the opsonins, 

 say by exposing serum containing agglutinin for 15 minutes to 

 60°. Our knowledge with regard to the effect of this exposure 

 upon opsonin is certain, but we are not so decided about the 

 effect upon the specific agglutinins. Duclaux"^ says that the 

 activity of agglutinating serum increases up to 55° and even 60° 

 at which it persists but becomes enfeebled, agglutination becoming 

 less sharp and less prompt. Weilf found that while an exposure 

 for 5 minutes at 80° destroyed the agglutinable substance on 

 typhoid bacteria, it did not destroy the agglutinating substance in 

 the serum. Joos| and, later, Eisenberg and Volk,§ distinguish 

 between thermostable and thermolabile agglutinins. Scheller|| 

 denies the existence of two kinds of agglutinin, as he found that 

 horse serum, which contains quantities of typhoid agglutinin, 

 lost but small traces of its power when heated at 60°-62°, and 

 that rabbit typhoid serum lost little or none of its power after an 

 exposure for two hours at 60°-62°. According to Dreyer,1I the 

 immune serum of animals treated with Bad. coli commune loses 

 half of its agglutinating power when heated for 30 minutes at 

 65°, and when the agglutination is observed at the end of two 

 hours. When examined at the end of 20 hours, there is no loss. 

 The apparent loss is therefore caused by a slowing of the reaction. 



* Microbiologie, iii. 711. 



+ Centr. f. Bakt. Orig. xxxvi. 084. 



X Zeit. f. Hygiene, xxxvi. 422. 



§ Zeit. f. Hygiene, xl. 155. 



II Centr. f. Bakt, Orig. xxxvi. 694. 



H Brit. Med. Journ. 10th Sept. 1904, 566. 



