4 BULLETIN" 369^ U. S. DEPXeTMENT OF AGRICULTURE, 



were found to contain no B. coli in 10 cc quantities and very low 

 total counts at both temperatures of incubation. The total counts 

 very seldom were above 50 per cc, and often were less than 10 per cc. 

 In certain instances legal actions have been brought against com- 

 panies preparing and selling bottled waters when the waters examined 

 have contained an excessive number of organisms, including B. coli. 

 These companies having been thus impressed with the necessity of pro- 

 ducing a clean commercial product have responded by placing on the 

 market later consignments from which no B. coli were isolated in 10 cc 

 quantities from 12 or more bottles. Repeated examinations of water 

 from many springs have failed to show any B. coli in 10 cc quantities. 



EXAMINATION OF COMMERCIAL BOTTLED WATERS. 



The methods employed in making these bacterial examinations 

 were those prescribed from year to year by the committee on water 

 analysis of the American Public Health Association. The high- 

 temperature counts have always been made on plain agar after 

 incubation at 37° C; but the earlier low-temperature incubations 

 were made on agar at 25° C, instead of on gelatin at 20° C, as 

 during the last two years. Dextrose broth, lactose bile, and lactose 

 broth have been used at different times for the preliminary tests for 

 B. coli; but in nearly every instance, when reported present, B. coli 

 have been isolated. Many of these have been verified by testing 

 special dextrose cultures with methyl red, as recommended by Clark 

 and Lubs.^ A summary of all these examinations follows: 



Of 110 domestic springs (see Table IV) — 



47 (43 per cent) contained no B. coli in 10 cc quantities. 

 63 (57 per cent) contained B. coliin 10 cc quantities. 

 61 (55 per cent) contained B. coli in 5 cc quantities. 

 59 (53 per cent) contained B. coli in 1 cc quantities.^ 

 49 (44 per cent) contained B. coli in 0.1 cc quantities. 

 31 (28 per cent) contained B. coli in 0.01 cc quantities. 

 10 (9 per cent) contained B. coli in 0.001 cc quantities.^ 



Sixty-nine (62 per cent) gave counts of less than 100 per cc on one 

 or more bottles after incubation at 37° C. for two days. 



Eighteen (16 per cent) gave average counts of less than 100 per cc 

 on six or more bottles at 37° C. 



Fourteen (12 per cent) gave no counts of less than 1,000 per cc on 

 six or more individual bottles. 



The highest average count on all samples from any one spring 

 was 191,238. 



1 Clark and Lubs, The differentiation of bacteria of the Colon-aerogenes family by the use of indicators 

 Jour. Infect. Dis., v. 17, No. 1, 1915, p. 160. 



2 Any potable water supply containing B. coli in 1 cc quantities is considered suspicious by health 

 departments and is at once investigated. 



3 Water containing B. coli in 0.001 cc quantities is too suggestive of dilute sewage to be accepted by 

 anyone. 



