50 CITY MILK SUPPLY 



These figures as regards ventilation in Tables 24 and 25 are worthy 

 of remark. The higher percentage of reactors in the barns with poor 

 ventilation as noted in the Minnesota results, are such as may be expected 

 but the Montclair figures show that often stables with ample air space 

 and window area house badly infected herds. Good ventilation and light- 

 ing are helpful in keeping down tuberculosis but a cow with open lesions, 

 after all, is the great big factor in spreading the disease. 



The Lesson of Tuberculin Testing. Such is the evidence given by 

 tuberculin testing; it shows that bovine tuberculosis has a firm hold wher- 

 ever dairying has become an important industry. In some places the 

 disease has been but recently introduced; many herds in the United 

 States are free from it. The problem is to keep them so and to eradicate 

 the plague from herds that are already affected. The task is stupendous 

 but it must be performed because infected milk and dairy products 

 menace the young and because the disease cuts deeply into the profits 

 of the producer and greatly increases the cost of living to the consumer. 

 The emphasis that has been laid on the public health aspect of the prob- 

 lem has probably tended to make breeders and dairymen feel that the 

 principal way in which they were concerned was in preventing measures, 

 designed to debar the marketing of infected dairy produce, from being 

 drastic. On the other hand, the consumer has no doubt often felt that 

 he was being imposed on in being compelled to pay the farmer for slaught- 

 ered diseased stock even though it was condemned by the representative 

 of the consumer and in his interest. Both viewpoints are wrong and those 

 who are endeavoring to improve the situation must lose no opportunity 

 to drive home the fact that both producers and consumers are supporting 

 an industry that is oppressively and outrageously taxed by the ravages 

 of a communicable disease. The tax will be levied whether efforts to 

 control the disease are made or not. By letting the disease run, the in- 

 convenience of paying to uproot it, is avoided but collection is made in 

 the end, in the form of feeding animals that are too sick to yield milk in 

 paying quantity, of lessened fecundity of the herds, of loss of valuable 

 stock, of suspicion that is engendered of purebred stock, of loss of meat 

 that is condemned as food and of bills that are pai4 the physician and 

 surgeon for care of tubercular patients, and the undertaker for burying 

 them. The welfare of all demands that the disease be attacked, not in a 

 desultory fashion but in a carefully thought out campaign, planned to 

 be fought out on the lines laid down for 10 years or more if necessary. 

 As yet no fully satisfactory plan for dealing with the menace has been 

 evolved anywhere. The methods that are actually in use may be profit- 

 ably considered. 



Control of Tuberculosis by Immunization. In the first place, it should 

 be noted that attempts have been made to immunize dairy animals but 



