40 



tion of the fat will show whether this has been practised, as it will 

 also in the case of mixtures of skim milk and whole milk. 



To determine whether an abnormally watery milk or a watered 

 milk is before us, we may use chemical or mechanical means. For 

 scientific investigations only the former are used, and must consist 

 in a complete quantitative analysis. For practical purposes, we can 

 confine ourselves to a determination of fat and total solids. 



Physical examination: The physical examination of milk 

 consists mainly in the determination of the specific gravity. The 

 microscopical examination is not fit for quantitative results, but can 

 merely be used for the determination of abnormalities, as blood, 

 pus, and colostrum corpuscles, or solid adulterants. It cannot be 

 used to determine with certainty the adulteration with water, 

 though it is a fact, that watered milk contains the larger and smaller 

 fat globules in the same proportion as whole milk, though further 

 separated from one another. The want, or deficiency, of the larger 

 or medium size globules, would indicate skimming. 



Conrad has shown how difiicult it is to obtain a good sample on 

 a slide, representing really an average of the milk to be examined ; 

 the same milk well mixed furnishing, by all the care that can be 

 bestowed, samples which show differences as regards the number, 

 size and distribution of the fat globules. 



The estimation of the number of fat globules in the field is also 

 quite arbitrary. 



Later on, in the chapter entitled " Milk inspection," a method 

 for the determination of the fat will be described, which, if not 

 absolutely accurate, admits at least of safe deductions. The spe~ 

 cific gravity of normal market milk (such which represents the milk 

 of several cows mixed), which possesses an average composition as 

 follows : 



'Water and volatile substances 87.50 



Salts 0.50 



Fat 3.60 



Albuminates 4.00 



Sugar of milk 4.50 



100.00 

 ranges, according to many thousand examinations, in different 

 countries, from 1.029 to 1.033. A milk, therefore, which contains 



