24 MILK HYGIENE 



albumin) were present. The inorganic salts (ash) are 

 present only in small quantity (0.31 per cent.). 



Ass's milk is essentially the same as that of the mare ; 

 it has in common with the latter the low fat and proteid 

 content and the large quantity of lactose. The composi- 

 tion is given somewhat differently by different writers. 

 Ellenberger, Seeliger and Klimmer found as the aver- 

 age of a large number of analyses : water 91.20 per cent., 

 fat 1.10 per cent., proteids 1.50 per cent., lactose 6.0 per 

 cent., ash 0.40 per cent. The reaction is decidedly alka- 

 line to litmus. On account of the small proportion of 

 salts, the casein is precipitated by rennet as a flocculent, 

 disunited mass. Milk of the ass more nearly resembles 

 human milk than does that of any other animal, and in 

 Southwestern Europe, for the most part, milk of the ass 

 is the principal substitute used for the nourishment of 

 infants. 



Woman's milk, which reacts amphoterically, is regu- 

 larly somewhat richer in lactose than cow's milk, but it 

 contains less proteids and also less ash, especially phos- 

 phoric acid and lime. While the lactalbumin in cow's 

 milk constitutes but one-fifth to one-sixth of the protein, 

 in human milk during the first part of the period of 

 lactation, albumin and casein are present in almost 

 equal quantities; later, casein increases a little. The 

 average percentage of fat is approximately the same as 

 in cow's milk, but it varies considerably, from 1.3 per 

 cent, to 7.8 per cent. Human milk is richer in lecithin, 

 but poorer in citric acid (about 0.5 per thousand) than 

 cow's milk. According to E. Gottlieb the following 

 numbers represent the average composition of 104 sam- 

 ples : water 87.92 per cent., fat 3.43 per cent., casein 0.58 

 per cent., albumin 0.52 per cent., lactose 7.12 per cent., 

 ash (salts), 0.25 per cent. Woman's milk is subject to 

 individual variations to a great degree, as is shown by 



