CURING BUTTER IN THIS COUNTRY AN J) ABROAD. 199 



wlu'ii the milk is newly drawn. If not dissipated 1)y exposure 

 to tlio air, it affects not only tlu; milk Init all tlie products 

 manufactured from it. It is liest known as the peculiar flavour 

 of new milk, which prevents, with some individuals, its use at 

 an early stage. In some adults it produces nausea and disturbs 

 licalth ; l)ut it is relished by, and is altogether innocuous to, 

 chilch'cn. Tliis odour is peculiar to the milk of all mammalia, 

 and has a powerful influence on it, so much so, tliat there is a 

 very great difference between that in which it exists and that 

 from which it is expelled. It resembles the mingled breath and 

 perspiration of the cow, is in a greater degree attached to milk 

 newly drawn, and is spoken of as a " cowy " odour. It is to the 

 factory managers of America we are greatly indebted for a 

 better knowledge and management of this enemy, for previous 

 to tlu'ir origin, even yet in this country, it has not attracted 

 sufficient attention. But the increased supply of milk now 

 required for the large towns, and the urgent demand for a better 

 article in milk, cheese, and butter, have in late years led to a 

 better idea of its nature and the means to be employed for its 

 dissipation. The inlluence of animal odour on butter is, witliout 

 doubt, deleterious; for if it l)e, by cooling the new milk too low 

 or too suddenly, carried into the cream and thence into the 

 butter, a bad flavour is the result. The fine, aromatic, delicious 

 taste of the oleine and its essential oils is replaced by a strong 

 indistinct flavour betraying the presence of some impurity, and 

 the former — the one natural to the butter — becomes so modified 

 and obscured as to be indistinguishable ; consequently, such 

 butter is said to be " off flavour." This odour escapes rapidly 

 with an increase, slowly with a decrease of temperature; when 

 very low it fails to escape and remains permanently in the milk. 

 If milk is kept warm it forms as readily after it leaves the udder 

 as in it, and ordinary milk will as much — nay, moic than new 

 milk — produce it if it is kept covered and warm ; but if milk is 

 altogether boiled it cannot form. It is considered to be the 

 result of germs which are produced at any time, l)ut in greater 

 and multiplying numbers when the cow is not in her onlinary 

 state of health. It lichaves as a ferment, multiplying with great 

 rapidity under favourable circumstances. KeeiJing the milk in 

 too large masses without stirring it, or having any disagreeable 

 odour within reach, will produce the ever multiplying spores ; 

 consequently, cleanliness and care in regard to this susceptible 

 ferment are indispensable. 



Exposure to the Air. — Organic Germs. 



Apart from animal odour, milk is of itself an unstable com- 

 pound. It is continually undergoing change from its secretion 



