A 46 B18 1900

PREFACE TO THE FOURTH EDITION,

IT has been the author's endeavor to bring this new edition fully up to the hour, and therefore several chapters, especially those treating on Immunity and Infection, have been rewritten entirely. The Widal agglutination test is fully described in connection with the bacillus of typhoid fever. Descriptions of the bacillus of yellow fever (bacillus icteroides) and the bacillus of the bubonic pest have been added. So carefully have the earlier workers laid the foundations that one finds but little to change in the descriptions of the various germs, and but little new to add. When this book first appeared, some nine years ago, bacteriology in this country at least was in its infancy, a bacteriologic laboratory was unknown here, there were no American text-books, and only one good English book; to-day, not only medical colleges, but many high schools have departments and laboratories of bacteriology, and the health department of a large city is incomplete without an expert bacteriologist. In these few years the knowledge known to the few has become the property of the many, yet much remains to be discovered; there are many diseases clearly infectious in their nature for which no germs have been found, and for the investigation of such diseases this country should spend its wealth freely. There should be a greater number of experimental laboratories and fellowships 7

to support young men while pursuing such investigations. Bacteriology in America is out of the cradle stage; the next decade must witness the rise of the investigators and the dis

coverers.

The author feels a certain pride in the fact that though so many good books relating to bacteriology have of late been published, his little work still finds so good a sale as to warrant a new edition, and this in spite of the fact that he is unconnected with any teaching institution.

M. V. BALL.

WARREN, PENNA.

PREFACE TO FIRST EDITION.

FEELING the need of a Compendium on the subject of this work, it has been our aim to produce a concise treatise upon the Practical Bacteriology of to-day, chiefly for the medical student, which he may use in his laboratory.

It is the result of experience gained in the Laboratory of the Hygienical Institute, Berlin, under the guidance of Koch and Fränkel; and of information gathered from the original works of other German, as well as of French, bacteriologists.

Theory and obsolete methods have been slightly touched upon. The scope of the work, and want of space, forbade adequate consideration of them. The exact measurements of bacteria have not been given. The same bacterium varies often much in size, owing to differences in the media, staining, etc.

We have received special help from the following books, which we recommend to students for further reference :

MACE: Traité pratique de Bacteriologie.
FRÄNKEL: Grundriss der Bakterienkunde.
EISENBERG: Bakteriologische Diagnostik.

CROOKSCHANK, E. M.: Manual of Bacteriology.

GUNTHER: Einführing in das Studium der Bacteriologie, etc.
WOODHEAD AND HARE: Pathological Mycology.

SALMONSEN: Bacteriological Technique (English translation).

M. V. BALL.

BUFFALO, N. Y., October 1, 1891.

62 Delaware Avenue.