MANUFACTURE OF CHEESE. 389 



part. There is reason to believe that albumen passes into a state of decompo- 

 sition and putridity witli greater facility than casein. 



The success which attends Borden's patent method of preserving milk so as 

 to keep in any climate and for any length of time depends in no small degree 

 upon the abstraction of the albumen contained in it as an indispensable pre- 

 liminary. Aside from this, its manuflicture consists in taking away the larger 

 portion of the water of the milk by evaporation in vacuo, and by the addition 

 of sugar. But these last would not avail for its preservation without the former. 

 It is also well known that the Devonshire method of making butter, which 

 involves a heating of the milk and consequent coagulation of the albumen, re- 

 sults in a larger product than any other method, and it is equally well known 

 that such butter cannot be kept for a length of time like butter made in the 

 usual way, doubtless owing to the difficulty or impossibility of separating the 

 coagulated albumen, which at once increases its weight and adds to its liability 

 to become rancid. The usual occurrence of albumen in milk has been denied 

 by some, but with what reason it is not easy to imagine. It has, so far as my 

 knowledge extends, been found in every specimen which has been tested for it. 

 A late writer on milk, in the Dublin Quarterly Journal of Science, (page 

 338 — 1862,) says, " The normal constituents of milk are water, a small quan- 

 tity of mineral matter, (ash,) casein, sugar, and butter. Albumen is only a 

 constituent in the colostrum or first milkings after parturition." 



It seems not improbable, to say the least, that the substance constituting the 

 little sacs Avhich contain the little globules of butter is a nitrogenous material 

 different from either albumen or casein, although this is a matter of conjecture 

 or of inference rather than of proof. If composed of either of these substances, 

 how comes it to exist in the milk in a condition so very unlike all the rest of 

 the same, which is in a state of solution, and not of undissolved films ? And 

 again: if these films do not consist of a substance of peculiar properties, why is 

 it that after thumping and banging about in the churn for an hour, more or 

 less, they nearly all at once, and not in tlie order in which they are mechan- 

 ically acted upon, give up their integrity, break, and liberate the oily particles ? 

 A good many questions might be asked regarding milk and its products 

 which, in the existing state of knowledge, it would puzzle any one to answer, 

 and which seem to require for their solution a more minute acquaintance with 

 its chemical composition. For instance, we know that casein is a nitrogenous 

 substance, and liable to putrefaction ; we know that it constitutes from thirty 

 to forty per cent, of cheese ; and yet cheese is preserved from decay for 

 months or years by an addition of three per cent, of salt. We know that pure 

 butter or the oily portion of milk is not a nitrogenous substance, and not more 

 liable to putridity than beef tallow; and yet carelessly worked butter, which 

 contains, say, a tenth part as much casein as cheese, cannot be preserved from 

 rancidity by five nor ten per cent, of salt. Why is this ? But as such queries 

 do not bear directly upon the manufacture of cheese, we will proceed to notice 

 some peculiarities which are equally obscure, and yet do have a practical bear- 

 ing upon it. 



Aside from the chemical composition of milk and the variations which at- 

 tend it, milk possesses other properties, which seem to be due to the vital ac- 

 tion by which it is secreted. These are variable also, and are of so subtle a 

 character as to defy the scrutiny of ordinary chemistry. What is known as 

 "animal heat" or "animal odor" is of this class. It is a well established fact 

 among practical dairymen that if milk in considerable quantity be shut up 

 closely in a vessel as soon as drawn, it will before long emit an exceedingly 

 offensive odor, and this before anything like decomposition could ordinarily 

 take place. The cause of this phenomenon is not certainly known. It is con- 

 jectured that, being a vital secretion, milk holds for awhile some remains of 

 vitality, which gradually pass off as an imperceptible. emanation when exposed 



