580 A MANUAL OF BACTERIOLOGY 



at once (within three hours). If this cannot be done the 

 specimen should be packed in ice ; the cold will then 

 inhibit multiplication to any extent. Special double- 

 chambered metal boxes are made for this purpose : the 

 bottle containing the sample (not less than 60 c.c. ; the 

 writer prefers to have not less than 200 c.c.) is placed in 

 the inner chamber, the outer chamber (which surrounds 

 the inner) being filled with a mixture of ice and sawdust, 

 and the whole is packed in a wooden box with felt lining. 

 According to Remlingler, 1 the addition of 10 per cent, of 

 common salt to the sample preserves the original bacterial 

 content of the water unaltered up to ninety-six hours after 

 taking the sample, without icing. Besides the sample 

 packed in ice, a " Winchester quart " of the water may 

 also be collected for examination for the spores of the 

 B. Welchii (enteritidis sporogenes). 



The routine bacteriological examination of the specimen 

 may be carried out according to the scheme (here somewhat 

 modified) drawn up by a committee of the Royal Institute 

 of Public Health. 2 



PROCEDURES. The following procedures should be 

 carried out : 



(a) Enumeration of the organisms which will develop 

 aerobically in gelatin at 20 C. 



(b) Enumeration of the organisms which will develop 

 aerobically in agar at 37 C. (Enumeration is carried out 

 by counting the number of colonies which develop in the 

 plates [see p. 79].) 



(c) Search for Bacillus coli, and identification and 

 enumeration of this organism if present. 



(d) Search for, and enumeration of, streptococci. 



As a routine measure it is not necessary to search for 



1 Comp. Rend. Soc. BioL, Ixx, p. 64. 



2 Journ. State Med., vol. xii, 1904, p. 471. 



