150 FRANK C. BECHT AND JAMES R. GREER 



Since the discovery of the opsonins by Wright and Douglas44 there has been a 

 great deal of work done with these bodies, and as a result there has arisen an extensive 

 and conflicting literature. It is beyond the scope of this paper to undertake a general 

 discussion of this subject. We will confine ourselves, therefore, to those results which 

 most nearly relate to our problem. So far as we have been able to determine, there has 

 been up to this time no study of the relative concentration of the opsonins in the different 

 body fluids of the same animal. 



Wright and Reid45 found that exudates may contain little or no opsonin. Opiess 

 found that the exudates following the injection of bacteria or turpentine were practically 

 opsonin free if unmixt with blood. Bohme 6 reports 15 cases of pleural and peritoneal 

 exudates showing a concentration of the opsonins ranging from less than half to even a 

 greater concentration than that of the serum. He also examined the edema fluid in 

 seven persons. In two of these cases there was very little opsonin while the remaining 

 five showed a considerable amount, but in no case was it equal to that of the serum. 

 This same investigator examined the cerebrospinal fluid in 16 cases and obtained opsonic 

 indices varying from 8 per cent to 76 per cent. He notes that these fluids were free from 

 blood. Bohme tries to correlate the concentration of the opsonin in these cases with 

 the amount of the protein in the fluid. 



Levaditi and Inman 21 and others have shown that while the aqueous humor 

 normally contains little or no opsonin, yet that secured after a previous withdrawal 

 contains the opsonin. 



Methods. The method of securing the fluids was the same as that described in 

 the foregoing. 



The leukocytes were from the pleural exudate of young, healthy dogs which 24 

 hours previously had been given intraplural injection of a suspension of aleuronaut 

 in sterile 0.9 per cent NaCl solution. The exudate was secured after bleeding the 

 animal to death, and was drawn into a warm solution of i per cent sodium citrate in 

 0.9 per cent NaCl. The leukocytes were centrifugated out, and washed a second time 

 in warm, sterile salt solution. 



The bacterial emulsion was obtained by suspending in 0.9 per cent NaCl solution 

 24-hour slant agar cultures of Staph. aureus. This emulsion was filtered through 

 absorbent cotton in order to remove the clumps and was then made up to the desired 

 opalescence. In all of the experiments a fairly rich suspension of the bacteria was 

 used, but no attempt was made to standardize this emulsion, and comparison of 

 individual experiments, except where the same suspension of leukocytes and bacteria 

 were used, would not be warranted. 



The technic was essentially that described by Walker with slight modification. 

 This method in our hands gave the most satisfactory results. Dilutions of the various 

 body fluids were used in the same way as the whole fluid. The usual time for incuba- 

 tion was 20 minutes. Care was taken to make the smear from the incubated mixture 

 as soon after the period of incubation as possible, so that the time factor was as nearly 

 equal as it could be kept. We here incur a slight source of error in the difference in 

 the age of the material, for BeattieS has shown that the older citrated leukocytes are 

 up to 24 hours, the greater the phagocytosis, but the maximum difference in time 

 between the first and last smear was never greater than one hour. Great care was 

 taken to keep the leukocytic suspension of the same consistency throughout the experi- 

 ment. The leukocytes were used as fresh as possible, usually in about two hours or 

 less after removal from the animal's body. The number of leukocytes varied from 



