32 Composition of Cheese. 



whey is very milky in appearance, yet as a rule this loss is small 

 in most dairies. Indeed, my analyses prove positively that whey 

 seldom contains much casein or curd which might be retained 

 by ever so careful filtration. I have filtered whey from good 

 milk through the finest blotting-paper, and obtained it as bright 

 as crystal. On heating the perfectly clear whey to the boiling- 

 point, however, a considerable quantity of a white, flaky sub- 

 stance, resembling in every respect albumen, or the white of egg, 

 made its appearance. Collected on a filter, washed with distilled 

 water, dried at 212 F., and weighed, this albuminous or curdlike 

 substance amounted on the average to about *9 or nearly 1 per 

 cent, in good milk ; in very rich milk there may be a little 

 more, in poor a little less. This albuminous matter is contained 

 in the whey in a state of perfect solution, and differs from casein 

 or curd in not being coagulated by rennet. I have called it an 

 albuminous matter, because, like albumen, it separates in flakes 

 from the whey at the temperature of boiling water. Any one 

 may prove the existence of this substance, which, however bright 

 the whey may be, it invariably deposits in abundance at the 

 boiling-point. 



Assuming, then, *9 to be the average proportion of this albu- 

 minous matter in whey, and deducting this proportion from the 

 total amount of nitrogenized substances in the eighteen samples 

 of whey, we obtain the amount of curd held in mechanical sus- 

 pension. Thus we get for 



No. 1 whey *30 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 2, 4, 8, and 15 whey .. .. none. 

 No. 3 and 13 whey '06 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 5 whey "525 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 6 and 9 whey 11 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 7 whey .. .. .. .. *156 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 10, 12, and 14 whey . . . . '01 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 11 whey '03 per cent, of curd, held in a state of 



mechanical suspension. 

 No. 16, 17, and 18 whey .. .. '04 per cent, of curd, held in a state of 



mechanical suspension. 



Thus only in one sample out of eighteen there was about \ per 

 cent, of curd held in mechanical suspension, and one sample 

 containing Aths per cent., all the other samples, practically 

 speaking, containing no suspended curd. Thus it is not so much 

 the curd as the butter which is lost when whey is badly separated 

 from the curd. 



