The word Household is used as an extension rather than a limitation of the title. In a thoroughly scientific manner the authors treat the subject-matter of general as well as of household bacteriology and include, therefore, the true bacteria as well as the yeasts, molds, and protozoa. The volume is, therefore, a general textbook of micro-biology in which special attention is given to those problems which are of particular interest to the student of household science. The main divisions of the book treat (1) the micro-organisms themselves, (2) fermentations with special reference to those affecting foods, (3) the relations of bacteria and other micro-organisms to health. A fully illustrated key (comprising 37 pages) to the families and genera of common molds, supplements the unusually extended discussion of the morphology and classification of yeasts and molds, and makes possible the satisfactory identification of all forms ordinarily encountered by the student. The work embodies the results of the most recent researches. The book is exceptionally well written, the different topics are treated consistently and with a good sense of proportion. While concise in statement, it is thorough in method and scope. It is, therefore, well adapted for use as a text not only _for students of household science_, but _also_ for those to whom it is desired to present the science of bacteriology from _an economic and sanitary rather than from a strictly medical point of view_. “The book is a concisely written work on micro-biology, a branch of economic science that the public is beginning gradually to understand, has important relationship to the total welfare and prosperity of the community.... The manual can be recommended as a very good elementary bacteriology. It comprises about all there is of practical domestic value.”--_Boston Advertiser._ THE MACMILLAN COMPANY =Publishers= =64-66 Fifth Avenue= =New York= A Laboratory Guide to the Study of Parasitology BY W. B. HERMS University of California, Berkeley, California; Author of “Malaria: Cause and Control” _Cloth, 8vo, xv + 72 pages, 80 cents net_ PART I--MEDICAL ENTOMOLOGY PART II--HELMINTHOLOGY PART III--LIFE HISTORY STUDIES ON LIVING PARASITES