From observation made of a great number of cases by authorities the average weight for girls at birth is a little over seven pounds, while that of boys is about seven and a half pounds. Some weigh more, some less. There is a loss of weight the first three days, this being greatest the first day. After the third day the child begins gradually to increase in weight and by the tenth day will have gained all that was lost the first three days, reaching the birth-weight about the tenth day. The artificially fed babies gain more slowly, even though they may be perfectly healthy and vigorous. The greatest increase that is made in the weight of children the first year is during the first three months. Normally the average child will gain from five to six ounces each week during the first six months, but only about half this much the second six months. The data given here must be considered only as an average, no standard can be set, but the variation must be within certain limits, otherwise it will be indicative of abnormality. During the first two years the weight of children is considered with reference to age, but after this it is studied with relation to height. This latter method is much more accurate. The age, however, must always enter into the consideration, for of two children of the same height but of different ages the older should be the heavier. There is much less variation in weight with reference to height than with reference to age. Normal weight differs with different individuals and is governed by various conditions so that a stated weight can not be decided upon as normal in all cases. The degree of deviation from the average weight that one may experience and still be within the normal range is a matter of opinion. If the weight of the child is more than 10% below the average for his height it is a fair indication that there is a lack of proper nutrition, either because he does not have proper food or because the tissues can not assimilate the nutrition due to interference with transmission. In a case of this kind the child should be carefully analyzed and adjusted. The disturbance may be in the digestive tract or due to an impairment in the serous circulation.