FRANK C. BECHT AND JAMES R. GREEK 



The aqueous humor contained opsonin in five of eight cases, but 

 in only one of these did the concentration approach that of the serum 

 of the same animal. The remaining four showed very much less 

 phagocytosis, while three experiments gave negative results. 



Opsonin was found in the pericardial fluid in two of seven dogs 

 in considerable amounts, in one it was practically equal to the neck 

 lymph of the same animal. In one of the remaining animals there 

 was a trace of opsonin. The other four animals contained no opsonin 

 in this fluid. 



It is difficult to increase to any marked extent the concentration 

 of the opsonin for Staph. aureus in a dog by immunization. 



We submit below two experiments in detail which we consider 

 quite typical of our results. 



TABLE 13. 

 COMPARATIVE OPSONIC POWER FOR STAPH. AUREUS OF THE BODY FLUIDS OF IMMUNIZED DOGS. 



(Both of these dogs received subcutaneously six slant agar cultures of Staph. aureus suspended in 

 0.9 per cent NaCl solution. Ten days later the fluids were all secured in apparently perfect condition. 

 Fluids kept over night in ice-box. Bacteria from a 24-hour slant agar growth. Incubation 20 minutes. 

 Carbol-thionin. Same bacterial suspension and leukocytes in both experiments.) 



Control for both=o.22. 



It will be noted that the results of these experiments are com- 

 parable with those with respect to the other antibodies studied. In 

 the two experiments cited above the concentration of the opsonin is 

 considerably higher in the serum than in the other fluids. Of the 

 two lymphs there is a slight excess in that from the thoracic duct over 

 that from the cervical lymphatics. In both of these experiments 

 while there is considerable opsonin in the pericardial fluid yet it is 

 less than in the serum and the lymphs. In both of these experiments 

 the cerebrospinal fluid and the aqueous humor contained opsonin, 

 but in very much smaller amounts than in the corresponding serum 

 and lymphs. 



Conclusions. There is a considerable amount of opsonin for 



