An important subject of inquiry in relation to the causes which may affect the taste and the wholesomeness of drinking-waters, was brought into prominence, by the excessive mortality, daring the early part of June of this year, among the fish in the Passaic. Numerous articles, calculated to alarm the inhabitants of towns using Passaic water, were published by the local press, and also in New York. It was stated that thousands of fish had fallen victims to disease of an epidemic character, and the number of those perishing would suffice to contaminate the water; while the probability was that the same agencies which made the water fatal to fish, would render it detrimental to human beings. Many explanatory theories were advanced, such as the washing into the rivers of Paris green, used to arrest the ravages of the Colorado beetle. Some attributed it to the use of arsenical or other poisonous dye-stuffs, by establishments at Paterson, or the introduction of unusual amounts of manufacturing refuse, waste acids, alkalies, or other chemicals. The latter was the favorite theory, and received support from persons who had presumably examined somewhat into the matter.
I made two visits to Paterson, during the progress of the epidemic, and spent several days in collecting information. Both banks of the river, as far down as the Dundee dam, and up to Little Falls, were examined. Unfortunately, the height of the epidemic had passed when newspaper attention was attracted, and circumstances had intervened which apparently had removed the exciting causes. I saw, however, sufficient dead fish, in advanced stage of decomposition, to render it probable that the mortality might not extravagantly be estimated by thousands. No naturalist appears to have critically examined into the nature of the fish-disease.
Valuable information, however, is contained in the following letter, in reply to certain inquiries addressed to him, from Mr.