APPENDIX 473 



streptococci 



The committee consider that it is a distinct advantage to search for streptococci. 

 They may be looked for by making hanging-drop preparations of the fluid media 

 employed for the preliminary cultivation of the B. coli (glucose-formate broth, etc.). 

 The presence or absence of streptococci in these tubes gives also a quantitative value 

 to the examination, just as in the case of B. coli, and the result obtained should be 

 stated. The streptococci should be isolated (best carried out on nutrose agar 

 plates), and their characters determined. 



B. Snterltidis Sporogenes 



As already stated, the committee do not consider that it is essential as a routine 

 procedure to search for the B. enteritidis sporogenes, though in certain instances it 

 may be of advantage to do so. A negative result in such cases is probaby of more 

 value than a positive one. 



This report is the outcome of prolonged deliberations, and every point has been 

 carefully considered and discussed by the members of the committee. 



In conclusion, the committee suggest that if the above recommendations were to 

 be adopted by all engaged in the bacteriological examination of water it would 

 conduce to uniformity of results, and would render comparable the data obtained by 

 different observers. An addendum might be added to a report on an analysis 

 conducted on these lines, to the eifect that the analysis had been carried out in con- 

 formity with the procedures recommended by the committee of The Royal Institute 

 of Public Health, 1904. 



The committee beg to acknowledge their great indebtedness to Professor R. 

 Tanner Hewlett, M.D., D.P.H., upon whom the great burden of the work of the 

 committee has devolved. 



RUPERT BOYCE, M.B., F.R.S., 

 Chairman. 



R. Tanner Hewi.eit, M.D., M.R.C.P., 

 Hon. Secretary. 



BACTERIOLOGICAL EXAMINATION OF MILK* 



Physical examination (temperature, reaction, colour, cream, deposit, 

 specific gravity, etc.) of the milk should, be made if necessary. The 

 microscopical examination of the milk before and after centrifugalisation 

 or sedimentation will likewise often yield useful results. 



1. Plate Cullivalion. — Dilute as required, and make plate cultivations in 

 Petri dishes or flat-bottomed flasks. Six or more gelatine plates should be 

 made and incubated at room temperature. Plates should also be made 

 with nutrient agar for incubation at 37° C. Other media may also be 

 used. The plates should be counted on the second, third, and fourth 

 days, and the necessary sub-cultures made. Agar plates incubated wholly 

 at 18° or 22° C, will in the long run show more colonies than when 

 incubated at 37° C. and then at 22° C. or at 37° C. throughout. 



2. Anaerobic Cultivation. — At the same time that the primary aerobic 

 plate cultivations are made, similar plates should be made on lactose 

 gelatine and lactose agar for anaerobic culture (see p. 117). 



3. Piimary Tube Cultivation. — Take ten tubes of 10 c.c. of the milk 



* For further particulars concerning the bacteriological technique in milk 

 examination, see Bacteriology of Milk, by Swithinbank and Newman, 1903, pp. 

 30-115. 



