CO-OPEEATIVE DAIKY SOCIETIES 49 



Having explained this dairy-technical development, we will 

 now return to a consideration of the principal objection to the 

 co-operative dairy system, viz. the danger of spreading tubercu- 

 lous milk, milk containing the microbes or bacilli of tuberculosis, 

 to calves and pigs on other farms, and so infecting these with 

 the disease. As a result of the works of Dr. Bang and other 

 investigators, it was well known that tuberculous milk could, 

 and probably would, infect calves and pigs when mixed and 

 spread as it was by passing through co-operative dairies. And 

 this would be so in all civilised countries, as all have their pro- 

 portion of tuberculous cattle. It was likewise well known 

 that if milk is heated momentarily to 85° C. (185° F.), all tubercle 

 bacilli contained therein will be killed. When cream has been 

 heated to a temperature of 85° (185° F.), then the butter made 

 from it as well as the buttermilk are free of all danger of in- 

 fection. It would, therefore, be a sufficient protection of the 

 stock against infection through the milk, if all milk returned 

 from dairies had been previously so heated. And as almost 

 all Danish dairies had already voluntarily introduced heating 

 both skim milk and cream, it would evidently be no hardship 

 to require that all dairies should so heat their milk and cream. 

 A Law was therefore passed in 1898, which was amended in 

 1904, and revised in 1912, according to which it is prohibited 

 to deliver from dairies, as food for cattle, milk and buttermilk 

 which have not been previously heated to a temperature which 

 was in the first Law fixed at 85° C. (185° F.), but has in the later 

 Law been reduced to 80° (176° F.), for the practical reason, 

 that easily appHed tests will show whether milk has been 

 heated to at least 80° C. (176° F.), but will not show that 

 it has been heated above that temperature. A thorough 

 heating to 80° C. (176° F.) when this temperature is main- 

 tained for some time is quite sujQ&cient, and is as effective 

 as a momentary heating to 85° C. (185° F.). The law further 

 provides that all cream from which butter is churned for 

 export must be heated to that temperature. By this measure 

 the danger involved in the co-operative dairy system has been 

 effectively met. 



The Co-oj>erative Dairy Societies (sometimes named for 

 short " co-op. dairies ") have combined in Dairy Associations for 



