Groth and Hahn have exhibited two large tables C 67 and C 68 and a similar one C 69, the results of their important investigations about breast-feeding and mortality in the administrative districts of Bavaria. Groth shows in Table C 70 "mortality of sucklings in Bavaria," and in Table C 71 "breast-feeding and cancer." In Tables C 72 and C 73 the Groth and Hahn statistics are treated by Dr. A. Bluhm from the point of view of the influence of the habit of breast-feeding on the frequency of births. In connection with Figure C 73 she remarks: "This diagram shows the number of bottle-fed babies in the various Bavarian districts counted at the time of vaccination. To give as correct a picture as possible of the probable influence which the habit of breast-feeding has on the birth-rate (annual number of births per 1,000 of the whole population) there are represented on this figure by green and yellow columns the average birth-rate for the five years, 1875 to 1879, because in that period a record birth-rate was established, so that it may be assumed that there was then no intentional restriction of births. We see within the four 'old Bavarian' districts, where on the average 64.1% of the babies were not breast-fed at all, the number of births is about 4 per 1,000 of the population higher than in the Palatinate and the three 'Frankish' districts, which together only show 18% of non-breast-fed children."
"These two figures deal with the influence of the length of suckling on the birth-rate, the longer the duration of the suckling period, i.e., the higher the number of children breast-fed for six months or more, the lower the birth-rate. This only holds good for the country (Curve B) not for towns (Curve A). This circumstance is explained by the fact that the voluntary restriction of births is much more frequent in towns than in the country, where consequently the influence of the length of the period of suckling on the birth frequency can find much stronger expression than in towns, where, as Curve A shows, it is entirely extinguished by artificial birth preventatives. From both tables it results that, to prevent the senseless waste of human life, the interval between every two births must be more than two years; further, that it is possible to increase it by breast-feeding; the number of births in a district is based in the main on the larger or smaller intervals at which the women of reproductive age have children, and it may, therefore, at the same time, be taken as an expression of these intervals. Keeping these two facts in view, and considering the influence of the mode of infant feeding on infant mortality, it appears to be in the interest of the race that by means of the long duration of breast-feeding, the birth intervals should be extended to at least two years. The facts established in these two tables have a considerable bearing on race-hygiene, especially in reference to the Neomalthusian contentions of the necessary inferiority of the later born, and as a confirmation of the utility of breast-feeding for the reduction of birth frequency. Extremely great appears the influence of breast-feeding on infant mortality."
This importance of breast-feeding is further illustrated by Figure C 74—duration of breast-feeding and infant mortality, after Dietrich; by Figure C 75—average number of carious teeth, after Bunge; and by the three figures, C 76, 77, and 78—"average duration of breast-feeding and physical development, duration of breast-feeding and average school reports, and duration of breast-feeding and frequency of rachitic disturbances of development," after the extensive and valuable researches by Röse.
It must be pointed out that a far more direct connection exists between breast-feeding, duration of suckling, infant mortality and physical development than through the mere provision of suitable nourishment for the child. A good suckling capacity is a symptom of a strong constitution which is transmitted from mother to child. Examination of Röse's table offers this suggestion.