Table of Contents xi 



CHAPTER XII 



PAGE 



INSECTS AND HUMAN HEALTH 523 



A Typical Germ Disease Malaria, 523 ; The Mosquito, 535 



CHAPTER XIII 



MICROORGANISMS IN RELATION TO MAN 546 



The Dust of the Atmosphere, 546; Molds, 549; Yeasts, 558; 

 Bacteria, 570. 



CHAPTER XIV 



THE PROTECTION OF HEALTH 588 



Infection and Immunity, 588 ; Modern Theories of Immunity, 

 599 ; Vaccines and Antitoxins, 604. 



