April 28, 1905.] 



SCIENCE. 



649 



weighing of evidence by the investigator 

 himself, a procedure which finds expression 

 in his final opinion, or, it may be his at- 

 tempt, often a desperate one, to make an- 

 alytical data intelligible to an unscientific 

 audience. The first is, of course, necessary 

 and legitimate, the second is always of ques- 

 tionable policy, and frequently is an un- 

 deniable mistake. In former days, when 

 'standards' were still much in vogue, and 

 when the dictum of Wanldyn, that such 

 and such limits should not be passed in the 

 several items of water analysis, it was in- 

 deed a difficult matter, for the analyst to 

 escape from 'explaining' the analytical re- 

 sults to the assembled council of city 

 fathers, and deep was the irritation felt 

 by those people that the figures given 

 could not be explained as clearly as they 

 might have been were the case one involv- 

 ing the composition of an iron ore. Of 

 course, those were times when the chemical 

 data alone were considered sufficient where- 

 on to formulate a pronouncement as to the 

 quality of the watei% and it is to be ad- 

 mitted that the chemist himself frequently 

 foimd before him a very complex problem 

 when he attempted to fit the resi;lts of his 

 analysis to the sanitary facts known to re- 

 late to the water in question. Bacteriology 

 was as yet undeveloped and its bearing 

 upon the 'sanitary survey' had not as yet 

 seen the light. A sample of water taken 

 anyhow, in any kind of vessel and by any- 

 body, was packed off to the chemist ; all 

 knowledge as to where it came from was 

 intentionally withheld and a complete re- 

 port of its sanitary qualities was confi- 

 dently expected. The writer once received 

 a sample of a town supply in a two-ounce 

 Lubin extract bottle which still contained 

 some of the original perfiimery. Is it to 

 be wondered at that in those early days a 

 good share of discredit was cast upon a 

 water examination? With the advent of 

 bacteriology upon the scene, interest was 



greatly awakened. The new science prom- 

 ised much, and it seemed that the time had 

 come for very positive and ready answers 

 to the perplexing questions which had both- 

 ered us so long. Not so many years ago 

 there met in the city of New York a sizable 

 number of men who had gathered for the 

 purpose of discussing the merits of a chem- 

 ical versus a bacteriological examination of 

 water. Advocates of the two methods ad- 

 vanced arguments in support of their spe- 

 cial views and offered illustrations calcu- 

 lated to expose the weak points of their 

 opponents. Unfortunately some remains 

 of that spirit of rivalry still exist ; but those 

 who have the widest knowledge of the 

 broad field of 'water supply' readily admit 

 that a competent investigation suitable for 

 determining as to the purity o:^ a city's 

 water service can not be undertaken in the 

 laboratory of either the chemist or the bac- 

 teriologist or the microscopist alone, but 

 must be the product of a draft upon the 

 sciences represented by all three of those 

 men, and must, furthermore, include the 

 findings derived from what may be termed 

 the 'sanitary .survey.' I am speaking to 

 scientific men, who need no instruction, 

 but perhaps over their heads a few laymen 

 may be reached who need it sadly. And 

 now let it be asked, who are to be classed 

 as the laymen? There is but one answer^ 

 to wit, all who have not given special study 

 to this particular subject. The field is so 

 wide, is increasing at so rapid a pace and 

 covers such variety of topics, that even 

 those interested in this line of work have 

 all they can do to keep in touch with the 

 changes taking place about them. The 

 writer well remembers the great risk he 

 once ran of making himself luipopular 

 with the medical profession. While ad- 

 dressing a city council upon the advisa- 

 bility of erecting a special form of filter 

 for the purification of the public water 

 supply, he was interrupted by a council- 



