348 



Scientific Proceedings (130) 



egg albumin and water follows a similar curve, our experiments 

 further suggest that the acid effects of alkaline buffer solutions 

 with high carbon dioxide tension on living cells depend rather 

 on the relative impermeability of the membrane to the metallic 

 cations preventing free entrance of the sodium bicarbonate than 

 on a specific solubility of carbon dioxide in the cell membrane. 



Abstracts of Communications. 

 Tenth meeting. 



Minnesota Branch, Minneapolis, Minnesota, March 14, 1923. 



169 (2129) 

 The mechanism of serum fastness. 

 By W. P. LARSON and RUTH GREENFIELD. 



[From the Department of Bacteriology, University of Minnesota, 

 Minneapolis, Minnesota.] 



Soon after the discovery of the agglutinins it was observed 

 that some strains of a given microorganism were not agglu- 

 tinated by a specific immune serum. Such non-agglutinable 

 strains are said to be serum fast. The mechanism of serum fast- 

 ness is not well understood. Ehrlich's explanation of this phe- 

 nomenon on the basis of suppressed receptors does enable us to 

 visualize the condition, but a suppression of receptors is prob- 

 ably far from what actually takes place. 



In our studies 1 on pellicle formation it has been shown that 

 pellicle forming bacteria are rich in acetone-ether soluble sub- 

 stances. Bacteria which ordinarily do not grow in pellicle were 

 caused to do so by growing them in broth to which had been 

 added glycerine or carbohydrates which they did not ferment. 

 By growing the staphylococcus on glycerine broth for a few 

 generations it began to grow in a pellicle, and finally formed as 



i Jour. Inf. Dis., 1922, xxxi, 407-415. 



