706 VETEEINAKY HYGIENE 



Examination of Milk. 



The chemical and bacteriological examination of milk for 

 human food falls to the Medical Officer of Health; but 

 quite apart from that, it is desirable for veterinary purposes 

 that an independent examination should be made. While 

 the Medical Officer of Health deals with it as a food, we 

 examine it as a secretion, and whereas he causes his 

 analysis to be made with material re^lOved from the milk- 

 can, the fluid we examine is taken direct from the gland. 



Assuming that an examination is made by the Medical 

 Officer of Health of the mixed milk of the dairy, and by the 

 A' eterinary Officer of Health of the secretion of a single cow, 

 the results will by no means agree, even when the analyses 

 are made by the same hand. The mixed milk of a dairy 

 is of such uniform composition that adulterations are 

 readily detected, while the secretion from a single cow may 

 differ considerably from that of the mixed milk. 



An examination of milk should be both chemical and 

 microscopical. The chemical should deal with the specific 

 gravity, reaction, total solids, fat, and the solids not fat. 

 A table has been drawn up representing the minimum 

 quantity of these found in a genuine sample of ' mixed ' 

 milk, viz. : Total solids, 11"5 per cent., consisting of — fats, 

 3 per cent., solids not fat, 8"5 per cent. 



A milk containing less than these, is regarded under the 

 Food and Drugs Act, 1875-1899, as not genuine until the 

 contrary can be proved. 



The average composition of mixed milk, obtained from the 

 examination of some thousands of specimens, is as follows : 



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