10 METHOD OF DESTROYING ALG^E IN WATER SUPPLIES. 



upon the subject for twenty-five years, when "MacDonald's Guide to 

 the Examination of Drinking Water" was published. In the mean- 

 time various Germans had carried on investigations relating to the 

 biology of water supplies, notably Professor Cohn, of Breslau, who, 

 in a paper entitled the "Microscopical Analysis of Well Waters," 

 anticipated much that has since been ascertained in regard to the effect 

 of environment upon the character and quantity of the organism found 

 in the water. About the time of the appearance of MacDonald's 

 book, interest in the effect of algae in drinking water first began to be 

 aroused in this country, and papers by Farlow" and others called 

 attention to the fact that these plants were responsible for many of 

 the disagreeable odors and tastes in water reservoirs. By the year 

 1878 there was on record a list of over 60 cities and towns in the 

 United States which had had serious trouble because of the presence 

 of certain forms of vegetation in their reservoirs, but since then thou- 

 sands of water supplies throughout the country have been rendered 

 unfit for use by this cause alone. Early in the year 1891 the special 

 report upon the examination and purification of water by the Massa- 

 chusetts State Board of Health was published, this being the most com- 

 plete treatment of the subject which had appeared up to that time. 

 This report has been supplemented by further investigations and 

 experiments, and the work accomplished by this board in perfecting 

 methods for insuring a pure water supply has established the standard 

 both in this country and abroad for similar lines of investigation. 



WIDE DISTRIBUTION OF TROUBLE CAUSED BY ALG^E IN WATER 



SUPPLIES. 



In order to demonstrate the very wide distribution of the trouble 

 caused by algae in water supplies throughout the United States, a 

 circular letter was sent to about five hundred of the leading engineers 

 and superintendents of water companies, asking for information in 

 regard to the deleterious effects produced by plants other than bacteria 

 in water supplies with which they were familiar. Many instructive 

 replies were received, indicating that those in authority were extremely 

 anxious to be provided with some efficient remedy for preventing the 

 bad odors and tastes in drinking water, and that they considered the 



FARLOW. Reports on Peculiar Condition of the Water Supplied to the City of 

 Boston. Report of the Cochituate Water Board, 1876. 



Reports on Matters connected with the Boston Water Supply. Bulletin 

 of Bussey Inst., Jan., 1877.. 



Remarks on Some Algae found in the Water Supplies of the City of Boston, 



1877. 



On Some Impurities of Drinking Water Caused by Vegetable Growths. 

 Supplement to 1st Ann. Rept. Mass. State Board of Health. Boston, 1880. 



Relations of Certain Forms of Algae to Disagreeable Tastes and Odors. 



Science, II, 333, 1883. 



