SCARLET FEVER OUTBREAK AT BRISTOL 383 



single occasion, all the cases sickening within a few days, absolute 

 exemption of W4 street was quite likely to occur in the circum- 

 stance of the X supply running short on that particular day, which 

 the distributor Z believes may have happened on or about 

 Saturday or Sunday the 13th or 14th of October. 



" The Wi round was amongst a different class of houses limited 

 in number, and admittedly supplied on occasion from B ; whereas 

 W2 and W3 streets got no chance of exemption from the X 

 supply, and suffered heavily. 



"The general rounds (Ci, C2, C3) of this distributor in Clifton, 

 were as a matter of routine practice restricted to the milk supplied 

 from farms B and C, but in order to make up quantity small 

 portions of X milk were occasionally added : — 



Houses supplied . . . S^j ^ ^ ^^^^ Cases, 6. 



Houses attacked . . . 4J ' ^ ' 



This milk was sent out on three distinct rounds, one of which 

 (Ci) remained exempt, the second had one case, and the third 

 ~ lowed three infected houses and five cases." 



These two examples set forth step by step the kind of investiga- 

 tions necessary in milk-borne epidemics. No fact is too trivial to 



neglected, as the reader of Mr Power's reports well knows. 

 Only by great patience and by following up every hint and 

 suggestion or possible channel can the ultimate truth be arrived at. 

 It is perhaps unnecessary^ to remark, that in London or any great 

 city such investigations are much more complex than in the 

 country. This is largely owing to the complications of the dairy 

 trade. It is not simply a question of the farmer and his customers. 

 The London milk supply is derived from various parts of the 

 provinces, even to a distance of 200 miles from the metropolis. 

 The farmer collects his milk from several farms and places it on the 

 railway. It is received by a London contractor, say in the early 

 hours of the morning, and is sorted by him at the railway terminus 

 or at his own depot, frequently the former. The vans are loaded 

 and the milk is distributed over various parts of London to milk- 

 shops and dairies. These milk-shops supply smaller retail shops or 

 street vendors or customers. To trace a small quantity of infected 

 milk from a farmstead in, say, Staffordshire, to a small tenement in 

 a London back street or court, is therefore a matter of considerable 

 intricacy. But it may be said that if the problem is attacked in 

 the way set out above in the two charts of Dr Davies, there 

 is some hope of ultimate success. But success also depends upon 

 an intimate knowledge of the milk trade. {See Control of Milk 

 Supply, pp. 461-468.) 



