xvm PREVENTION OF TUBERCULOSIS 333 



The Manchester figures are the most important, as they deal with 

 a very large number of samples, extending over a number of years. 



The table shows that there has been some diminution 

 in the percentage of tuberculous samples, but that, apart from 

 the first few years of working, it has been neither continuous 

 nor very marked. During the first few years some of the worst 

 offenders would doubtless be weeded out and warned off from 

 supplying the particular city. The amount of tuberculous 

 milk for Manchester drops to about 6 per cent, and to about 

 9 per cent for Sheffield, and there it remains. No regular, 

 consistent diminution in the infective quality of the milk is 

 observable. If the Manchester figures are carried back to 

 1897, and only the samples bringing milk into Manchester 

 (country samples) are considered, the beneficial results of the 

 first few years working are more clearly brought out. Thus 

 Delepine 1 gives the percentage of tubercle-infected mixed-milk 

 samples arriving in Manchester as 13'3 for 1897, 20 '0 for 1898, 

 and 11*1 for 1900. Delepine also records that "the lesions 

 observed in inoculated animals have of recent years become gener- 

 ally slight when compared with those produced ten years ago." 



(6) Their Influence upon the Prevalence of Udder Tuber- 

 culosis. The following tables supply some data. 



1 Eeport of Medical Officer, Local Government Board, 1908-9, p. 393. 



2 From information kindly furnished by Dr. Niven. 

 3 Report of Medical Officer of Health (Dr. Scurfield), Sheffield, 1909. 



