Contents 



CHAPTER PAGE 



XVI. THE COMMON SOURCES OF BACTERIAL IN- 

 FECTION . . . . . .175 



XVII. WATER AND ICE AS SOURCES OF INFECTION 184 



XVIII. HAZARDS OF THE AIR .... 199 



XIX. A DANGEROUS NEIGHBOR . . . .211 



XX. THE END OF THE STORY . . . .216 



INDEX ......... 223 



