164: NORMAL MILK : ITS ADULTERATIONS, ETC. 



Colostrum differs from milk in containing less sugar, a fat 

 which is very poor in volatile acids, and a high amount of nitro- 

 genous compounds, which differ from those of milk. The dis- 

 crepancy between the results of Engling and Houdet is due to 

 the methods for the separation of the nitrogenous compounds 

 not being known. 



Steinegger has shown that colostrum has a high aldehyde 

 figure. 



Milk containing colostrum is not used for dairy purposes ; at 

 least four days should be allowed to elapse after parturition 

 before the milk is employed for consumption. Miss E. G. Cook 

 has, however, patented its use for the manufacture of milk for 

 infants. 



Generally speaking, the milk of newly-calved cows is poorer 

 in fat than that of cows towards the end of their period of lacta- 

 tion. Kuhn's experiments have shown that the casein also 

 increases as the period of lactation advances, while the milk- 

 sugar decreases ; the mineral matter also increases towards the 

 end of lactation. Most of the analyses on p. 15-i which show 

 a high percentage of proteins were obtained from cows which 

 were getting dry. 



The milk of cows in ill-health may have a very abnormal 

 composition. Wynter Blyth has collated the information con- 

 cerning these in his Foods, their Comfosition and Analysis (q. v.). 

 They are, however, of interest from a pathological point of view, 

 rather than of practical importance in dairying. 



Limits and Standards of Milk. — The President of the Board 

 of Agriculture and Fisheries has laid down, after enquiry had 

 been made by a Departmental Committee on Milk Standards 

 appointed by him, the limits of 3'0 per cent, of fat and 8'5 per 

 cent, of solids not fat ; a presumption is raised, till the contrary 

 is proved, that any milk yielding figures on analysis below these 

 limits is not genuine, but has in the former case been deprived 

 of a portion of its cream, and in the latter has been adulterated 

 by water. 



The figures are identical with the limits previously adppted, 

 unofficially, by the Society of Public Analysts ; in practice the 

 official adoption of the figures has resulted in a strengthening 

 of the limits ; the wording of Clause 4 of the Sale of Food and 

 Drugs Act, 1899, has transferred the onus of proof from the 

 prosecution to the defence. These limits do not represent the 

 absolute minima yet found, as will be readily seen by referring 

 to the figures previously quoted, but are limits below which 

 mixed milk of a herd of cows may be reasonably expected not 

 to fall. Vieth, in discussing the question how far they could 

 be applied to all milks, has written : " My object is by no means 



