1893.] MICROSCOPICAL JOURNAL. 127 



On Some I{<»c(Mit Advances in Water Analysis an<I the Use 



of the Micnjscope for the Ih'teetion of Sewage 



Contamination. 



Bv GEO. W. RAFTKR, 



KOCHKSTEK, N. V. 



^/{fati before the Buffalo, N. ?*. , Micro.^copical Club, Dec. 12, iSg3.'\ 



It is quite within the memory of nearly every member of the 

 Biitl'alo Microscopical Club to recall the time when chemical 

 aualvbis alone was the only available method for determining the 

 sanitary value of a drinking water. Then came the develop- 

 ment of methods of bacteria culture, accompanied by a clearer 

 appreciation of the necessity, before deciding as to the vvhole- 

 someness or unwholesomeness of a given water, of a thorough 

 study of the environment, or, in other words, of a study of the 

 various pollutions aflbcting the sources from which a supply is 

 drawn ; and rtnallv the latest, and possibly quite as important as 

 anv, the development of a method whereby the minute life other 

 than the bacteria can be quantitatively enumerated with an ac- 

 curacy which, while not absolute, is still sufficientlv so for the 

 practical purpose of studv of sanitary significance and compar- 

 ison. 



It is unnecessary to occupv time on this occasion either in de- 

 scribing just how the quantitative enumeration of the microscopical 

 forms in potable water is actually accomplished, or in pointing 

 out the part taken by the author in the final working of what is 

 known as the Sedgwick-Rafter method of making the micro- 

 scopical enumeration. It is sufficient to simply refer those in- 

 terested to the original paper with detail in the proceedings of the 

 Rochester Academy of Science.* The method there described was 

 also exhibited at the working session of the Buffalo meetingof the 

 American Microscopical Society and is referred to in the proceed- 

 ings for that year (1SS9). 



There are, however, a few points of historical interest which 

 may be casually referred to here, namely, in relation to the work 

 of the Microscopical Section of the Rochester Academy of 

 Science, and the essential assistance received from a number of 

 friends in that body, without which it is probable the methods of 

 microscopical study of the minute life would have been some- 

 what less perfect than they are at the present time. The points 

 thus deserving: record are briefly as follows : 



• Biological Examination of Potable Water Proc. Roch. Acad. Sci., vol. i, pp. 34-44. 



The mei hod is also described in Part II of the Special Report of the Massachusetts State Board 

 of Health (1890), on Water Supplies and Purification of Sewage, etc.. at pp. 808-811, where 

 may also be found an account of Professor William T. Sedgwick's Sand Method, etc. 



The method may aUo be found described in the author's The Microscopical Examination 

 of Potable Water. D. Van Xostrand Co., 1892. 



Also see The Microscopical Examination of Water, by Gary N. Calkins, Assistant Biolo- 

 gist, in 23d Annual Report Massachusetts Stale Board of Health (1891), pp 397-421. In this 

 paper the Sedgwick-Rafter method is fully de>cribed, certain improvements suggested, and pos- 

 sible sources of error pointed out : it may be referred to as the latest ana most complete 

 exposition of the detail of the method of microscopical enumeration. 



