294 MILK AND THE PUBLIC HEALTH CHAP. 



and used only for milk. The measuring out of milk on 

 station premises should be prohibited. 



C. PURVEYING OF MILK 



One of the most difficult matters to adjust in any scheme 

 for a purified milk supply will be regulations in regard 

 to the mixing of milk from different sources. The Medical 

 Officer of Health, faced with a milk-spread outbreak of in- 

 fectious disease, at once seeks to find the source of the evil 

 and stop further damage. If his sphere of activity is a large 

 city his search is often impeded, sometimes stopped, at the 

 outset. The dairyman purveying the milk cannot tell him 

 the source, since all or much of the milk is mixed. From the 

 public health point of view it is most important to be able to 

 promptly trace back the milk to the cows which yielded it,/ 

 and the possibly infectious persons who handled it. 



On the other hand, the large purveyor says it is impossible 

 to keep all milk consignments separate. The milk as received 

 is removed from the original churn, usually strained, often 

 cooled, sometimes pasteurised, all this being done in bulk with 

 other consignments. He points out that book-keeping would 

 be impossible if every contributor's churns had to be separately 

 entered and the milk kept apart. He goes further, and says 

 that the mixing is essential in order to obtain a uniform 

 chemical standard. It has also been suggested to the writer 

 by a large purveyor that the dilution of any pathogenic pro- 

 perties in one churn by the bulk of harmless milk is a great 

 safeguard to the spread of infection. It may be so, but in 

 view of the rapid multiplication of bacteria in milk is hardly 

 likely. On the other hand, it might, by causing the cases to 

 be distributed over a very wide area, render it more possible to 

 overlook the milk origin of the outbreak. It is certain that 

 a great deal more could be insisted upon, than is now done, in 

 the way of keeping accurate records of the source of all milk, 

 without inflicting any undue hardship upon the milk purveyor. 



Improvement of the conditions under which milk is pur- 

 veyed will necessitate a concentration of the milk trade, and 

 the small purveyor will tend to disappear. The small general 

 shops selling small quantities of milk as a quite subsidiary 



