D. J. DAVIS 659 



dreds of years ago before the great epidemics of the Middle Ages. Colds, pneumonias, 

 and virus infections of various kinds are striking examples of such phenomena. 



Deserving of special emphasis, also, is the increasing recognition through recent 

 contributions of a close association between respiratory bacteria and viruses and cer- 

 tain epidemic infections of the central nervous system. Enough is known at present 

 to indicate clearly that the solution of at least some of our serious paralytic and en- 

 cephalitic conditions lies along lines directed to control or combat the growth and 

 dissemination of organisms entering the body through the respiratory passages. 



