804 THE COMPLETE GRAZIER. BOOK n. 



minute forms of plant life on even the best of butter leads to the 

 liberation of the volatile acids, and produces rancidity, and in the case 

 of the carelessly and imperfectly made article, only partially washed and 

 drained, the sugar and casein left in the butter do but hasten the 

 changes. 



The changes which take place in milk are now known to be largely 

 due to the growth within and upon it of specific organisms which 

 have the faculty of multiplying with amazing rapidity. They affect 

 the milk by their living actions, extracting from it those constituents 

 necessary to the building up of their own bodies, and leaving the 

 remaining constituents, which they do not require for that purpose, 

 arranged in new and varied combinations. The organisms are 

 undoubtedly of many different kinds, and unlike each other in their 

 effects upon the milk. From the time the milk is drawn from the udder 

 till the time when coagulation is effected there may be established (by 

 migration from the air or from any source in contact) healthily multiply- 

 ing colonies of, it may be, some score of different organisms. The 

 primary cause of variability in the product is the presence in the curd 

 and whey of a crowd of living organisms which have been affecting the 

 milk from the first, and are to continue to act upon it after its conver- 

 sion into curd, and the subsequent matting, draining, pressing, and 

 drying of the cheese. There are two fairly distinct classes of living 

 things which affect the curd and whey of cheese, many of them not 

 found in the milk at all, but the results of an after colonization in the 

 curd itself, either during its crumbling or even after it has been formed 

 in the vat. These two classes are the bacteria on the one hand and the 

 true fungi on the other, and it may be taken generally that the bacteria 

 are present in the milk and curd from the first, and that the fungi 

 come later on, after the former have partially completed their life. 

 Both, however, assist, often simultaneously, in the change of curd 

 into cheese, and subsequently give rise to the flavours which charac- 

 terize the product. 



There is still another pregnant source of evil in connection with the 

 germs which infest the milk and so much deteriorate it. This is the 

 water supply. Now, as a rule on farms, the proper degree of attention 

 is not paid to this ; anything, almost, in the form of water being thought 

 good enough for the stock to drink. On this point the reader will find 

 some remarks in another chapter of this work. Here it is sufficient to 

 say that stagnant water, impure water even although it be not stagnant 

 but running water, well water, all of which contain in many instances 

 decaying or decayed organic matters, may, when taken into the system, 

 give rise to products which will greatly injure the quality of the milk. 



There has been much speculation as to whether the milk from tuber- 

 culous cows can be consumed with impunity, and, having regard to the 

 fact that milk is so frequently employed as food without cooking, more 

 especially for children, there appears to be considerable risk attending 

 its use. Professor Duguid, discussing this subject in " The Journal of 

 the Royal Agricultural Society, 1890," says (page 314) that tuberculous 

 milk must be looked upon as dangerous and likely to be the means of 



