xii MILK AND THE PUBLIC HEALTH 



PAGE 



Estimation of the number of B. coli and allied organisms : pro- 

 cedure, composition of media to use, dilations to examine, pro- 

 cedure to isolate, comparison of methods, identification tests to use, 

 comparative value of the different identification tests Determina- 

 tion of the number of streptococci : procedure, isolation, differentia- 

 tion tests, preparation of media Estimation of the number of B. 

 enteritidis sporogenes spores : methods, dilutions to use, patho- 

 genicity tests. 



CHAPTER XI 



THE CELLULAR AND SEDIMENT EXAMINATION OF MILK . . 191 



Methods for estimating the cellular contents Comparative value of 

 the different methods Examination of the stained centrifugalised 

 deposit Comparative count of the different cellular elements 

 Methods for estimating the sediment in milk Value of the 

 cytological estimation Value of the sediment estimation. 



CHAPTER XII 



CHEMICAL TESTS TO ESTIMATE THE PURITY AND FRESHNESS OF 

 MILK. THE EXAMINATION OF CREAM AND SPECIAL 

 FORMS OF MILK . . . .... 202 



Acidity determinations : variations, value, method of estimation 

 The determination of the formalin-methylene blue reduction time 

 The detection of heated milk The detection of preservatives. 



Condensed milk : method of examination, bacterial content 

 Dried milk Examination of cream. 



CHAPTER XIII 



THE DETECTION OF PATHOGENIC BACTERIA IN MILK . 214 



B. tuberculosis : microscopic method of detection, inoculation 

 methods, reliability of the methods Differentiation of tubercle 

 bacilli of human and bovine origin Detection of tubercle bacilli in 

 butter Detection and isolation of diphtheria bacilli Isolation 

 of the typhoid bacillus Isolation of other pathogenic bacilli. 



CHAPTER XIV 



INTERPRETATION OF RESULTS AND BACTERIOLOGICAL STANDARDS 



FOR MILK . . . . . . . ... 228 



The three groups of contamination Comparative value of the total 

 bacteria estimation as a measure of general contamination Value 

 of the B. coli estimation : for byre milk, for vended milk, coli 



