vi PREFACE TO FIRST EDITION 



A knowledge of the new science early became so 

 indispensable for the sanitary expert that a special 

 course in the Bacteriology of Water and Sewage has for 

 some years been given to students of biology and sani- 

 tary engineering in the Biological Department of the 

 Massachusetts Institute of Technology. For workers 

 in this course the present volume has been especially 

 prepared, and it is fitting, we think, that such a manual 

 should proceed from an institution whose faculty, 

 graduates, and students have had a large share in shap- 

 ing the science and art of which it treats. We shall 

 be gratified, however, if its field of usefulness extends 

 to those following similar courses in other institutions, 

 or occupied professionally in sanitary work. 



The treatment of the subject in the many treatises 

 on General Bacteriology and Medical Bacteriology is 

 neither special enough nor full enough for modern 

 needs. The classic work of Grace and Percy Frank- 

 land is now ten years old; and even Horrocks' valuable 

 " Bacteriological Examination of Water " requires to 

 be supplemented by an account of the developments 

 in quantitative analysis which have taken place on this 

 side of the Atlantic. 



It is for us a matter of pride that Water Bacteriology 

 owes much of its value, both in exactness of method 

 and in common-sense interpretation, to American 

 sanitarians. The English have contributed researches 

 of the greatest importance on the significance of certain 

 intestinal bacteria; but with this exception the best 

 work on the bacteriology of water has, in our opinion, 

 been done in this country. Smith, Sedgwick, Fuller, 



