Hunter, _Laboratory Problems in Civic Biology_. American
Book Company.
Bigelow, _Introduction to Biology_. The Macmillan Company.
Conn, _Bacteria, Yeasts, and Molds in the Home_. Ginn and
Company.
Conn, _Story of Germ Life_. D. Appleton and Company.
Davison, _The Human Body and Health_. American Book Company.
Frankland, _Bacteria in Daily Life_. Longmans, Green, and
Company.
Overton, _General Hygiene_. American Book Company.
Prudden, _Dust and its Dangers_. G. P. Putnam's Sons.
Prudden, _The Story of the Bacteria_. G. P. Putnam's Sons.
Ritchie, _Primer of Sanitation_. World Book Company.
Sharpe, _Laboratory Manual in Biology_, pages 123-132.
American Book Company.