302 THE COMPLETE GRAZIER. BOOK 11. 



Whenever the making of cheese and of butter of the highest and 

 purest quality is aimed at and surely this should be the case with 

 every dairyman and with the manager of every factory it is of the first 

 importance to have the milk absolutely free from all impurities. It has 

 long been known that there is scarcely any substance with which we 

 have to deal which is so liable to be tainted as milk. Hitherto it has 

 been considered that all that was necessary to prevent this tainting was 

 to secure the most perfect cleanliness in everything used in connection 

 with milk, to see to the condition of the cow-houses, their distance from 

 places where bad odours arise, the cleanliness and thorough ventilation 

 of the milk-room, the cleanliness, sweetness, and purity of the vessels 

 used for keeping the milk, of the churns and the cheese-vats. But despite 

 the closest attention to all these points and they are of such vital 

 importance that attention to them cannot be too much insisted on 

 recent experience has shown that there are other causes of tainting, 

 which are even perhaps more dangerous in their effects than those 

 named. Such extra taints, if so they may be named, no doubt have 

 been noticed so far as their defects are concerned, but their causes 

 remained unknown ; and it is curious to note that these causes have 

 been brought into prominence in consequence of the introduction of 

 new methods of using milk on a large scale, prominent amongst 

 which stands the process for making " Condensed or Preserved Milk," 

 a trade now of great commercial importance. The same gentleman 

 who reported in the Royal Agricultural Society's Journal on the 

 American butter-factories (vol. vii., second series, 1871) Mr. X. A. 

 Willard of the Cornell University, and of the Maine Agricultural 

 College in a subsequent report (vol. viii., 1872), on the American 

 milk condensing factories, goes somewhat fully into the tainting of 

 milk. 



Mr. Willard points out the general results of the investigations of 

 the learned Hallier and Pasteur, who by means of microscopic observa- 

 tions of the most elaborate character were enabled to show the nature 

 of those causes which are in operation, which change milk from its 

 normal condition, or which render it filthy and unwholesome. These 

 investigations, as may be known to many of our readers, were made in 

 connection with the " germ " theory of disease, with which perhaps 

 more markedly or popularly the name of Pasteur is associated. 



From the instant the milk leaves the cow micro-organisms begin 

 their work, and increase with marvellous rapidity. But a very great 

 difference between the condition in which these fungi appear and do 

 their work in milk and in its after products must be here noticed, as it 

 bears closely upon the very point we have now under consideration, 

 namely the tainting of those products. Thus if the spores of the 

 fungi are already in pure milk, to begin with, or are added to the rennet 

 if cheese be made, the fungi appear to do no harm, but in the case of 

 cheese, at all events, seem rather to act in a legitimate way, if it may 

 be so termed ; as giving or imparting the peculiar flavour by which the 

 cheese is distinguished. But if the spores come from putrid matter, 



