Royal Microscopical Society. 163 



II. — Microscopical Examination of Water for Domestic Use. 

 By James Bell, F.C.S. 



(Read hefore the Eoyal Microscopical Society, March 1, 1871.) 



The microscopical examination of water for domestic use is, in my 

 opinion, a suitable subject to bring before this Society. The 

 subject is essentially a practical one, and affords a wide field in 

 which microscopists might occasionally spend a portion of their 

 time with much profit. 



A sample of water which is largely contaminated with sewage, 

 exhibits, when placed for a few days in a warm chamber, such a 

 mass and ■ variety of life, that the mind is almost bewildered in 

 trying to master in detail the numerous creatures that have sprung 

 into existence within so short a space of time. From the diversity 

 of the ingredients usually composing sewage, it would, indeed, be 

 difiicult to find a mixture so well adapted for the development of a 

 variety of organisms. 



Mr. Heisch was, I believe, the first who attempted to point out 

 a possible means of detecting, by the use of the microscope, whether 

 water had been contaminated with sewage or not; his method 

 being founded upon the development therein of a distinctive 

 organism in the presence of sugar. 



He found that when a' small proportion of pure cane-sugar was 

 added to water containing sewage, and the mixture was maintained 

 at a temperature between 60° and 70° Fahr., and placed in a posi- 

 tion where plenty of light was admitted to the bottle in which the 

 liquid was contained, the mixture became turbid in times, varying 

 from twenty-four to sixty hours, and contained cells and a delicate 

 fungus mycelium, followed by the ultimate development of the 

 odour of butyric acid. From this, Mr. Heisch concluded that 

 sewage contained particular germs, which when brought into 

 contact with sugar in water immediately began to grow. 



This observation was necessarily regarded as a most important 

 one, not only because it promised to efi'ect a change in the present 

 mode of determining the presence of sewage in water ; but to lead 

 to the discovery and identification of the germs which generate 

 epidemics. 



Mr. Heisch deserves great credit for initiating such an im- 

 portant line of investigation, and the combined researches of micro- 

 scopists on the subject may ultimately lead to important practical 

 results with respect to the laws of health, by determining the 

 exact conditions under which the germs of various organisms are 

 developed. 



Shortly after the subject was brought before the Chemical 



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