The scope of this book is limited, although the author hopes "that it is comprehensive enough to give the student an insight into general bacteriology, with special application in his own sphere, viz.: the mouth." The size and content hardly warrant this claim and it is recommended rather as a supplement to the more comprehensive textbooks of bacteriology in rather general use. Technical methods and culture mediums are adequately covered; the portion concerning those specially adapted for use in studying the oral flora is highly commended. Pathogenic bacteria are disposed of in two chapters and the same amount of space is given to the subjects of immunity, vaccines and antiserums. The section on the original bacteriology of caries has a number of faults. In it the author has failed to draw a sharp line between the past and the present. The inclusion of lengthy descriptions of organisms such as B.