MILK AND MILK-PREPARATIONS. 421 



oxygen. At the same time, as a result of the activity of germs that develop 

 rapidly in the milk(?), an increase of the fat, together with that of the alcoholic 

 and ethereal extracts at the expense of the casein, is brought about. Accord- 

 ing to Schmidt-Mulheim some casein is transformed into peptone but onlv in 

 unboiled milk. 



Milk-analysis. Every 100 parts of milk contain: 



HUMAN. Cow. GOAT. Ass. 



Water 88.3 88.0 86.25 89.01 



Casein 0.9-1.2 \ 3.0 2.53 ) 



Albumin 0.3-0.5 f I ' 1 03 i 26 / 3>s ? 



jitter 3-21 3-5 4-34 1.85 



Milk-sugar 4.67 4 .c * 78 1 



Salts 0.2 0.7 0.65} 5-05 



Colostrum contains much serum-albumin and little casein, but, on the other 

 hand, all other solid substances in larger amount, especially the butter. 



Pfliiger and Setschenow found in 100 volumes of milk the following substances 

 by volume: carbon dioxid from 5.01 to 7.60; oxygen from 0.09 to 0.32; nitrogen 

 from 0.70 to 1.41. The carbon dioxid can in part be displaced only by means 

 of phosphoric acid. 



Among the salts, those of potassium preponderate over those of sodium (as 

 in the red blood-corpuscles and in meat) ; also a considerable amount of calcium 

 phosphate is present, for the formation of the bones of the infant. Wildenstein 

 found in 100 parts of ash from human milk sodium chlorid 10.73; potassium 

 chlorid 26.33, potassium 21.44, calcium 18.78, magnesium 0.87, phosphoric acid 19, 

 ferric phosphate 0.21, sulphuric acid 2.64, silica a trace. The amount of salts is 

 influenced by that in the food. 



Milk exhibits no difference in the amount of albumin before and after nursing. 

 The amount of sugar, however, diminishes after nursing, while the fat increases con- 

 siderably. With the progress of lactation, albumin appears most abundantly 

 in the first six months, in lesser amount in the second six months, and after the 

 first year it decreases still more. The amount of fat varies, but rather increases 

 after the first year. The sugar exhibits a pretty uniform, inconsiderable increase. 

 In primiparae the amount of solid constituents (9.67 per cent.) is greater than in 

 multipart (8.56 per cent.). Young mothers form more albumin and fat, older 

 mothers more sugar. A starchy diet yields a fatter milk, while with a proteid 

 and fatty diet the amount of albumin and of sugar increases. Camerer and 

 Spldner found in milk a body resembling the basis of bone, together with 

 hitherto unknown bodies consisting of carbohydrates combined with proteids. 



If it be necessary to employ the milk of animals, it should be noted that cow's 

 milk (best when containing much fat) must be diluted with water and mixed with 

 milk-sugar. Heubner and Hofmann recommend for children from one to nine 

 months old, as a general rule, only one mixture, consisting of i part of cow's milk 

 and i part of a solution containing 69 grams of milk-sugar in i liter of water. 

 Soxhlet recommends a mixture of 2 parts of cow's milk and i part of a 12.3 per 

 cent, solution of milk-sugar. The casein of cow's milk varies qualitatively; 

 further, it appears in larger flakes and is, there fore, more difficult of digestion than 

 the small-flaked casein of human milk. The casein of human milk does not split 

 off paranuclein in the process of digestion, as does that of cow's milk. Boiled cow's 

 milk is somewhat more difficult of digestion than unboiled cow's milk, but, never- 

 theless, because sterilized, is to be preferred. The milk should be boiled for ten 

 minutes, be cooled quickly to below 18 C. and be kept cool. In the case of chil- 

 dren more than nine months old, the addition of water is progressively diminished. 

 Cow's milk may also be diluted with advantage with beef-tea. For children that 

 cannot take milk, v. Liebig has recommended especial soups prepared from cow's 

 milk, water, wheat-flour, hop-flour and sodium bicarbonate. The starch is trans- 

 formed, in the course of preparation, into sugar and dextrin. The more rapid 

 the growth exhibited by mammals the richer is their milk in albumin. 



Milk-tests. The amount of cream is measured by permitting the milk to stand 

 for twenty-four hours in a cool place in a high glass cylinder graduated into 100 

 parts. The cream that collects on the surface should amount to from 10 to 14 

 volumes per cent. The specific gravity of whole cow's milk is between 1029 and 

 1034, of skimmed milk between 1032 and 1040. It is determined by means of 

 the areometer at a temperature of 15 C. Every degree Celsius more or less 

 makes a difference of -0.1 or + 0.2 on the areometer. Should only an approximative 



