74 THE STORY OF GERM LIFE. 



of care in handling the dairy. It must be recog- 

 nised that most of these troublesome bacteria 

 come from some unusual sources of infection. 

 By unusual sources are meant those which the ex- 

 ercise of care will avoid. It is true that the sour- 

 ing bacteria appear to be so universally distrib- 

 uted that they can not be avoided by any ordinary 

 means. But all other troublesome bacteria ap- 

 pear to be within control. The milkman must 

 remember that the sources of the troubles which 

 are liable to arise in his milk are in some form of 

 filth : either filth on the cow, or dust in the hay 

 which is scattered through the barn, or dirt on 

 cows' udders, or some other unusual and avoid- 

 able source. These sources, from what we have 

 already noticed, will always furnish the milk with 

 bacteria; but under common conditions, and when 

 the cow is kept in conditions of ordinary cleanli- 

 ness, and frequently even when not cleanly, will 

 only furnish bacteria that produce the universal 

 souring. Recognising this, the dairyman at once 

 learns that his remedies for the troublesome in- 

 fections are cleanliness and low temperatures. 

 If he is careful to keep his milk vessels scrupu- 

 lously clean ; if he will keep his cow as cleanly as 

 he does his horse; and if he will use care in and 

 around the barn and dairy, and then apply low 

 temperatures to the milk, he need never be dis- 

 turbed by slimy or tainted milk, or any of these 

 other troubles ; or he can remove such infections 

 speedily should they once appear. Pure sweet 

 milk is only a question of sufficient care. But 

 care means labour and expense. As long as we 

 demand cheap milk, so long will we be supplied 

 with milk procured under conditions of filth. But 

 when we learn that cheap milk is poor milk, and 



