3 The Age of a Nurse should not exceed Thirty I would further venture to state that it should not be much under twenty five I have already shown elsewhere 1 that the age of the highest sexual development in a female is twenty six at which age she is in the best condition to fulfil her maternal duties After thirty this power slowly deteriorates and before twenty five she can scarcely be said to have completely acquired that physical health which has been weakened during the progress of puberty and the changed position which she has been made to occupy in society It is but right to add however that we do not find the milk itself very much altered chemically or microscopically between the ages of fifteen and forty Still at the extremities of the scale the differences are obvious In the very young the butter casein and solid matters generally excepting the sugar which exists in diminished quantity are on the increase in the older women there is a larger proportion of water and sugar the amount of butter and casein is diminished

Infant Feeding and Its Influence on Life, Or, The Causes and Prevention of Infant Mortality By Charles Henry Felix Routh