PREFACE 



THE present volume is not a record of original work, nor 

 is it a text-book for the laboratory. Theoretical and 

 practical text-books of Bacteriology plentifully exist both in 

 England and America. There are two large works widely 

 used, one by Professor Crookshank, entitled Bacteriology and 

 Infective Diseases ^ the other by Dr. Sternberg, A Manual of 

 Bacteriology, There are also, in English, a number of smaller 

 works by Abbott, Ball, Hewlett, Klein, Macfarland, Muir 

 and Ritchie, and Sims Woodhead. This book is of a less 

 technical nature. It is an attempt, in response to the editor 

 of the series, to set forth a popular scientific statement of our 

 present knowledge of bacteria. Popular science is a some- 

 what dangerous quantity with which to deal. On the one 

 hand it may become too popular, on the other too technical. 

 It is difficult to escape the Scylla and Charybdis in such 

 a voyage. 



I am much indebted to Professor Crookshank, who, in 

 reading the manuscript, has helped me by many valuable 

 criticisms. My thanks are also due to Sir C. T. D. Acland, 

 Bart., for many kind suggestions, and to Mr. E. J. Spitta, 

 M.R.C.S., who has been good enough to take a number of 

 excellent photo-micrographs forme. Some other illustrations 

 have been derived from the Atlas of Bacteriology, brought out 

 jointly by Messrs. Slater and Spitta. For these also I am 

 glad to have an opportunity of expressing my thanks. It 

 should be understood that the outline drawings are only of 

 a diagrammatic nature. 



GEORGE NEWMAN. 

 London, 1899. 



