254. Conditions Affecting Mother's Milk

Certain causes which are to be noticed and that may operate to modify the mother's milk such as food, medication, exposure, and nervous condition, are those which are under control. Other possible causes are those that are not under control; and which may be termed "natural."

255. Period Of Lactation

Among the latter it is very definitely shown that as the period of lactation progresses the proportions of ash and protein in the milk diminish, especially during the first few weeks.

Several authorities give figures that substantiate this statement.1

Table XLVII. Effect Of Period Of Lactation

TABLE XLVII

Effect of Period of Lactation

Period of Lactation

Pfeiffer

Adriance

Protein

Ash

Protein

Ash

Per Cent

Per Cent

Per Cent

Per Cent

1st month

2.97

0.237

1.55

0.21

2d month

2.04

0.184

1.54

0.17

3d month

1.99

0.184

1.49

0.19

11th month

1.47

0.145

0.64

0.18

12th month

1.73

0.160

1.18

0.14

12th month

1.65

0.155

1.02

0.16

1 " Des Kindes Ernährung," Czerny-Keller, p. 419.

A gradual rise in the percentage of fat occurs in the progressive portions of milk that are drawn; that is, the more nearly the mammary gland is emptied, the richer the milk is in fat. Account should be taken of this fact in selecting a sample for analysis, that is, a full breast should be entirely emptied by artificial means and a sample taken of the whole quantity after thorough mixing. It may also be said that, as a rule, the richness of human milk in fat is inversely as the total amount of milk secreted.

256. Individuality

There is also the effect of individuality, as shown by the tables on p. 268, which will be considered more fully later.