466 



APPENDIX 



-Filter in posi- 

 tion for filter-brushing 

 method. 



7 



sterilised brush, transfer the particulate matter which has collected on 

 the candle into 10 c.c. of sterile water or broth. This is now a concen- 

 tration or emulsion of the organismal content of the 

 litre of water, and may be used for examination for 

 special organisms. 



(a) B. enteritidis sporogrenes.— Place 0-5 or 



1 c.c. of the concentrated water in each of three 

 tubes of 10-15 c.c. of fresh sterilised milk. It is 

 important to use fresh milk, recently boiled, and 

 cooled down before inoculation. After inoculation 

 with the water to be examined, put the three tubes 

 into the water bath for fifteen minutes at 80° C, and 

 after allowing them to cool, place them in a Buchner's 

 tube or cylinder containing freshly-prepared pyro- 

 gallic solution (pyrogallic acid, 120 grains, strong 

 liquor potassae, 10 c.c). Accurately seal up the 

 Buchner, and place it, containing the tubes, in the 

 incubator at 37° C. The next day, or in forty-eight 

 hours, examine for B. enteritidis sporogenes. If that 

 organism is present, the following characteristic 

 appearances — the enteritidis change — will be ap- 

 parent (Klein). The cream of the 

 milk will be torn and altogether 

 dissociated by the development of 

 gas, so that the surface of the 

 medium becomes covered with 

 stringy white masses of coagulated 

 casein, enclosing a number of gas 

 bubbles. The main portion of the tube formerly occu- 

 pied by the milk will contain a colourless thin watery 

 whey, with a few lumps of casein adhering here and 

 there to the sides of the tube (see Plate 21, p. 307). If 

 the tube be opened, there will be found to be an odour of 

 butyric acid and an acid reaction. If some of the con- 

 tents of the tube are stained, as slide preparations, the 

 bacilli will be seen. 



(6) B. COli communis (p. 46). — Take from 01 

 to 0'5 of the concentrated or sample water, and 

 add to tubes of phenolated gelatine ('05 per cent, 

 phenol), or litmus-lactose agar, and make plates. 

 Colonies developing in these plates (red in latter medium) should be 

 suspected of being B. coli communis, and tested accordingly ; 



Or, inoculate from the concentrated or sample water, three tubes of 

 Parietti's broth,* and incubate at 37° C, and those tubes which show 



* Parietti's Formula consists of — phenol, 5 grams ; hydrochloric acid, 4 grams ; 

 distilled water, 100 c.c. To 10 c.c. of broth, -1-0 -3 c.c. of this solution is added. The 

 tube is then incubated in order to test its sterility. If it be sterile, a few drops of the 

 suspected water are added, and the tube reincubated at 37° C. for twenty-four hours. 

 If the water contains the B. typhosus or B. coli, the tube will show a turbid growth. 





H 



v^ 



47. — Buchner 

 Tube. 



