Scientific Proceedings. 



109 



Human leucocytes and staphylococcus aureus were used and the 

 time of incubation was thirty minutes, at 37°C. An alkalinity of 

 the fluid exceeding 1/20 normal KOH prevented the occurrence of 

 opsonization. An acidity of 1/30 normal HC1 was sufficient to 

 stop the opsonic function of the serum. Neutralization of the ex- 

 cessive alkalinity or acidity caused reappearance of opsonic activity. 

 On the other hand, an alkalinity or an acidity approaching that of 

 the normal alkali or acid produced a condition of irreversibility of 

 the inactivation. The opsonic index estimated in the usual alkaline 

 reaction of normal serum is far lower than that in a neutral medium. 



The high stability of opsonins against desiccation and the high 

 thermostability of dried opsonins are very striking. Almost no 

 reduction of opsonic strength is experienced after a serum is com- 

 pletely dried at 23 °C. within a few hours. In dry state opsonins 

 are well preserved even after two years. Dried serums of crotalus, 

 ox and horse gave positive results in this regard. The temperatures 

 of ioo°, 120 0 , 1 3 5 0 and I50°C. do not destroy opsonins in the 

 dry state. At I50°C. the serum becomes difficult to dissolve, but 

 opsonins may still be detected in it. 



Complements withstand desiccation and dry heat in a manner 

 similar to the resistance of opsonins. 



76 (219) 



On decomposition of uric acid by animal tissues. 

 By P. A. LEVENE and W. A. BEATTY. 



[From the Rockefeller Institute for Medical Research.] 



About two years ago in a communication before this society 

 we indicated the most favorable conditions for the decomposition 

 of uric acid by tissues. 



Several papers on the same subject have recently been pub- 

 lished in which it was demonstrated that uric acid may suffer 

 decomposition through the action of tissue extracts in the presence 

 of dilute sodium bicarbonate. 



This confirms the results in our previous paper. In our recent 

 work uric acid was subjected to the action of splenic pulp in the 

 presence of 2 percent, ammonium hydroxide and 2 per cent, acetic 

 acid. 



