452 CITY MILK SUPPLY 



of years and from this should be figured the average number, or the normal 

 incidence of cases, in each district in each of the 52 weeks so that at any 

 time that may be necessary it may be quickly told whether there are more 

 cases than normal for that week. 



Each case of infection, as it occurs, should be charged to the dealer 

 who happens to be serving the patient with milk. This should be 

 done not with the idea of fixing the responsibility for the case on the dealer 

 but rather to discover the occurrence of any unusual number of cases 

 among the dealer's customers. If the number of cases appears to be 

 excessive, care should be taken to ascertain whether it really is so, by 

 figuring whether the proportion of all the cases in the city that he is get- 

 ting corresponds to the size of his milk route or not. 



In some cities dairymen are required to file lists of their customers 

 with the board of health at stated intervals. This gives information as 

 to the size and location of the route and is sometimes convenient in 

 checking up statements of patients as to the milk they were using when 

 they were stricken with disease. 



It is highly important to be able to trace milk back to the producer 

 with celerity and certainty. So there must be some way of recording the 

 point of origin of each shipment of milk. In New York City the Depart- 

 ment of Health requires that to each can of milk there be attached a tag 

 showing where the milk was shipped from and the date of shipment. The 

 milk companies are also required to keep a record of the distribution 

 of this milk to the various retailers. Bottled milk must be dated and 

 be marked with the name of the creamery or bottling plant and the 

 records of the companies must show on what wagons and routes milk 

 bottled in the country is distributed. Retail dealers are required to 

 keep the can tags for 60 days. 



It is important to have some routine way of notifying the dairyman 

 of the occurrence of cases of contagion on his route, otherwise he is likely 

 to violate the provisions of the code relative to taking away bottles from 

 infected homes. Epidemics have been caused in this way. If bottles 

 are left daily at infected premises and not taken away until the case is 

 over, a considerable number accumulate and there is some possibility of 

 their infecting the dairy or of their being put into circulation without 

 proper sterilization. The danger is greatest when the dairyman is not 

 very intelligent and when, as is often the case in small cities, he lacks 

 facilities for sterilizing. In such cases the board of health should sterilize 

 the bottles with bleaching powder before they are taken from the premises. 



There is a further point to be considered in controlling the spread of 

 contagious disease through milk and it is pertinent to other phases of 

 milk regulation as well. It is, as to how to prevent milk that is excluded 

 from one town finding market in another. That this often happens there 

 is no doubt. Sometimes it can be prevented by notifying a State depart- 



