202 



NORMAL MILK : ITS ADULTERATIONS, ETC. 



It is noticed that none of the analyses add up to 100 per cent., 

 but are considerably low ; the milk-sugar has been calculated 

 as anhydrous sugar, and here lies the reason for the deficiency. 



On shaking the solid residue obtained by drying milk on the 

 water-bath, in which the milk-sugar certainly exists as anhydrous 

 sugar, with water a rise of temperature always takes place ; 

 anhydrous milk-sugar mixed with water always causes a rise 

 of temperature, whilst hydrated milk-sugar causes a fall of 0'55° 

 if more than can be at once dissolved is added. The milk powders 

 examined, with one exception (No. 2), all caused a fall of tem- 

 perature, and it is seen that the addition of the water of hydration 

 to the total gives figures which are but slightly in excess of 

 100 per cent. ; both the change of temperature and the slight 

 excess over 100 per cent, indicate that the bulk of the milk- 

 sugar, though not all, exists as hydrated sugar. Sample No. 2 

 differed in appearance from the others, being a heavy powder, 

 instead of being light and flaky, and had doubtless been more 

 dried, and probably contains a considerable proportion of anhy- 

 drous sugar ; it is noticed that the addition of the water of hydra- 

 tion would make the total nearly 101 per cent. Sample No. 7 

 gives a low total, which is probably accounted for by the presence 

 of invert sugar. 



It will be noticed that samples 2, 3, 4, and 7 contain small 

 quantities of cane sugar ; this in sample 2 was admittedly added 

 in the form of saccharate of lime, and was certainly so added, 

 judging from the analytical figures, in No. 7. 



In Table LIV. the composition of the original milks, on the 

 assumption that they contain 9'0 per cent, of solids not fat, 

 are given : — 



TABLE LIV. — Composition of Original Milks. 



From this table it is seen that No. 4 is made from separated 

 milk, and No. 6 from milk deprived of a portion of its cream. 



