The use of blood agar for the study of streptococci.

In this monograph with numerous charts and 34 full-page plates Brown classified streptococci into α, β, A prime and γ based on the type and degree of hemolysis produced by the bacteria on a blood agar plate. He also definitively demonstrated the value of the blood agar plate for the classification of bacteria. Digital facsimile from Google Books at this link.

(Thanks to Juan Weiss for this reference and its interpretation.)