METHODS OF INVESTIGATION AND PREVENTION 385 



question of the milk supply is predominant, ordinary methods 

 must be allowed their right exercise. 



We propose to treat of the control of the milk supply in suc- 

 ceeding chapters. The matter is a large one, and cannot be treated 

 in the present chapter. Before, however, turning to that subject 

 we desire to refer briefly to the relationship of bacteriology to the 

 investigation and prevention of outbreaks of infectious disease. 

 Such methods have only become available in late years, but they 

 are in every way applicable to milk-borne outbreaks, and, indeed, 

 have already been applied in such cases. 



Modern Bacteriological Methods and the Investigation and 

 Prevention of Infectious Diseases 



The rapid growth of our knowledge of bacteria, particularly 

 the pathogenic species, has afforded many additional advantages 

 in the investigation and prevention of outbreaks of infectious 

 disease. In a general way the new agencies are either of advan- 

 tage as aids to diagnosis or as auxiliary to prophylaxis. 



Bactepiological Diagnosis 



{a) The bacteriological " swab " examination of the human 



throat has proved of the greatest utility in all throat affections, 

 principally in diphtheria. It may prove serviceable in epidemics 

 or threatened epidemics. Briefly, its advantage is that an 

 outbreak can be checked at an early stage owing to the 

 possibility of making a much earlier diagnosis than was 

 formerly the case. It is now well known that the diphtheria 

 bacillus may exist in the throats of healthy persons, in 

 sore throats, and in the throats of persons suffering clinically 

 from scarlet fever. Meade Bolton found that of 214 healthy 

 persons who had some time been exposed to infection 45-5 

 per cent, showed Klebs-Loffler bacilli in their throats.^ Parke 

 and Beebe examined the throats of 48 children apparently in 

 good health, in 14 families in which diphtheria was present, and in 

 50 per cent, found the B. diphthericer Miiller examined bacterio- 

 logically 100 children in the general wards of the Charite Hospital 

 in Berlin, Of these six, on entry, had the bacillus in their throats 

 without exhibiting any symptoms of the disease. Two days later, 



^ Med. and Surg. Reporter, 1896, vol. Ixxiv., p. 799. 

 2 New York Medical Record, 1894, vol. xlvi., p. 396, also p. 385. 



2 B 



