376 INVESTIGATION, ETC., OF MILK-BORNE EPIDEMICS 



of the Infectious Diseases (Notification) Extension Act of 1899, 

 In London the notification provisions are incorporated in the 

 Public Health (London) Act of 1891. Thus it happens that at the 

 present time notification of certain infectious diseases (including 

 diphtheria, scarlet fever, and enteric or typhoid fever) is compulsory. 

 The onus of notifying is cast upon the medical attendant, or in his 

 absence the head of the family. The notification is made to the 

 Local Authority in whose district the infectious disease occurs, and 

 in general it is made direct to the Medical Officer of Health of the 

 district. This then is the first step in the investigation of milk- 

 borne, or otherwise conveyed, outbreaks of infectious disease, and 

 by the receipt of a number of such certificates the medical ofiticer 

 becomes aware of the existence of an epidemic. 



The second step is the investigation of each ease of disease 

 and of the cases as a whole. In the former it is customary for the 

 medical officer or his inspectors to make a minute inquiry as to 

 the individual. The precise method of inquiry differs of course in 

 different districts. The same form would not be equally suitable 

 in a rural as in an urban district. On the opposite page is given 

 a copy of such a form as is used daily in one of the metropolitan 

 areas. 



By means of such facts the medical officer becomes aware of 

 the most likely channels of infection and of some at least of the 

 most likely persons to contract the infection from the original case. 

 He obtains moreover a large amount of valuable information 

 respecting the disease under consideration and the sanitation 

 surrounding his cases. It cannot be doubted that in the long run 

 such records must prove of the utmost value in showing the causes 

 of disease and the channels of infection. To ascertain the milk 

 and water supply, the school or place of work, and the date of the 

 onset of the disease are of immense value in an endeavour to 

 search out the cause or to check the spread of the disease. It is 

 unnecessary here to discuss in detail each item of the said form. 

 But a word may be said upon the importance of knowing the exact 

 date of the onset of the symptoms of illness. This date is of 

 greater importance than the date of notification. For example, 

 in a recent inquiry conducted by the writer on the occasion 

 of a small outbreak of milk-borne scarlet fever, 19 notifica- 

 tions were received extending over nine days. In a large population 

 such a series would scarcely constitute an outbreak. But on making 

 careful inquiry in the case of each of the 19 persons suffering from 

 the scarlet fever, it was found that all these 19 persons commenced 



