134 Report of the Bacteriologist of the 



the starter of selected bacteria so that the desired flavor might 

 be always obtained. 



The problem that presents itself is not different from that which 

 confronts every farmer who attempts to grow a field of oats. If 

 he sows his seed upon land already filled with rapidly growirs 

 clover, Canada thistles and ragweed his chances of a good oat 

 crop are poor. If he first fits his land and kills off the other 

 plants tlie oats will have a better chance. To make a success of 

 this it is not necessary to kill off every weed in the field for if 

 the oats are much in the majority and get the start of the others 

 they will control the situation and suppress the weeds. 



The bacteria are plants of more simple form than those in the 

 above illustration, but they obey the same laws of competition in 

 growth. If conditions are so arranged that the starter when 

 added to the cream finds the same filled with rapidly growing 

 enemies, the effect of the starter will be largely or wholly lost ; 

 while if it is added to cream from which all or nearly all of its 

 competitors have been removed, the starter will assume control 

 of the situation and suppress its enemies. 



In the Danish machine the milk is introduced at one end of a 

 cylinder surrounded by steam and flows continuously from the 

 other end having been momentarily heated to the temperature 

 desired. 



The temperatures used have had an upward tendency and sin^^ 

 Dr. Bang announced that when working with tuberculous cows 

 furnishing the diseased germs in their milk the milk was ren- 

 dered harmless when passed through one of these machines ' 

 85° C. (185° F.), this has been taken as the Danish minimum 

 legal temperature for heating all the by-products that are to be 

 returned to the farm for feeding purposes. 



In a country where the most determined effort is being made 

 to stop the spread of tuberculosis among cattle the value of this 

 protection to a dairyman who has succeeded in freeing his own 

 herd from the contagion, but yet is compelled to raise his calves 



