This is a translation of the German edition. It deals largely with the preparation of specimens for microscopic examination and with mediums used for the growth of bacteria. The value of the manual to American workers is less than it would have been if the authors had seen fit to include some procedures in rather general use in this country. The special sections, such as those relating to examinations of water, air and soil and to immunologic reactions, are apparently introduced in the line of suggestions, since no detailed methods are given. The colored plates accompanying the section on general diagnosis are striking and satisfactory.