The discussion a t the last Scottish meeting on the effect of diet on pregnancy was, from a practical point of view, of special interest to the obstetrician; the present discussion is of the greatest importance to the paediatrician. I should like to mention some of the problems with which we are confronted.1 think it is probably true to say that the foetus in utero has first call on the food and food reserves of the mother. It is a striking fact that even grossly undernourished mothers have apparently well nourished babies. Even after the birth of her child an undernourished mother may provide adequate nourishment to her infant but too often in these circumstances the milk supply fails. But this failure is not confined to the undernourished, for even those who are well fed and apparently in perfect health are often unable to feed their infants. Diet is not everything. Not enough is known about the physiology of human lactation; I do not think it has been studied in the thorough way that bovine lactation has. The scientific breeding and feeding of cattle, perhaps because it is a commercial proposition, has led to enormous improvement in the quantity and quality of milk yielded by dairy cows. It is strange that a process of natural selection has not produced a race of women who are good miLkers. One would have thought that as breast fed infants have a far better chance of survival than those arti6cially fed, the offspring of bad milkers would gradually have, been eliminated. Actually, before the middle of the 19th century almost all artificially fed babies died. But it is a melancholy fact that fewer mothers seem able to nurse their babies now than 100 years ago and 1 do not think they were better fed then than now. I n recent inquiries it has been found that only about 50 per cent. of mothers of the artisan class breast feed their babies after 3 months, and 1 think it is probable that still fewer of those in the wealthier grades of society can do this. There can be no doubt that anything we can do to get breast feeding more universally employed will have important results on our infant mortality and on the health of young children.We are here today to consider the factors influencing lactation and its effect on the nutrition of the child. VOL. 2, 19441 45Cambridge for a baby to receive the milk of an undernourished mother, even though in quality it does not reach the highest standard, than to be fed with cow's milk. We are often told that the baby has been weaned because the milk did not suit it. Doctors and midwives do this far too light heartedly. For example, we often find that in congenital pyloric stenosis the baby has been weaned because he vomited the breast milk. In this case and many others the fault is with the baby, not with the milk.But when we turn to the consideration of the amount of milk secreted, that is where the usual difficulty lies. The usual reason for weaning is that the milk failed. The maintenance of a sufficient supply of breast milk is one of the chief problems for those dealing with th...