66 JAMES M. SHERMAN 



The conclusion of this paper with bibhography will appear in 

 the next number of the Journal of Bacteriology. 



Acknowledgment is made to Professors E. G. Hastings, A. 

 S. Pearse and E. B. Fred of the University of Wisconsin from 

 whom criticisms and suggestions have been obtained during the 

 progress of this work. 



