We cannot suppress the remark that the fluctuations of the curve for the feeble-minded are much too small to admit of the drawing of an ætiological conclusion, but the fluctuations of the intelligence curve and the illegitimate curve partly exceed the limits of probable error. The peaks of both birth curves in February, correspond to a peak in the procreation curve in May. Perhaps one may attribute them to the existence of a remnant of a period of "heat" (or a rutting season) in man.
+Lead.+ Whereas the +germ cells+ are well protected against many harmful influences from without which affect the soma of the mother, they +and the foetus produced from them suffer considerably from+ some. Amongst their deadliest enemies are +certain poisons+, and +notorious in this respect is lead+. Table C 98 gives two sets of statistics on this point, they justify the law in Germany, and in other States, forbidding female labour to deal with lead and lead-containing materials. Paul's figures, showing that lead poisoning of the father is also extremely adverse to the production of a healthy progeny, are remarkable.
+Female Labour.+ A baneful influence on reproduction is brought to bear by the growing quantity of professional female labour away from home and by the economic emancipation of women. Evidence of this is given in Table C 99--"+female labour and child mortality+"--the data of which are taken from Prinzing's work. Infant mortality is higher the larger the percentage of females employed in factories during the child-bearing period. This is partly due to interference with breast-feeding and partly to the unfavourable influence on pregnancy.
Dr. Agnes Bluhm has given in Figure C 100 "+Female Labour and Reproductive Activity+," the statistics of Roger and Thiraux, as well as the results of the investigation of the Imperial Statistical Office on the "Relationship of illness and deaths in the Local Invalidity Fund for Leipzig and surroundings." Dr. Bluhm gives the following explanation: "The top figure on the left is based on material of the Local Invalidity Fund for Leipzig and surroundings, dealing with over a quarter of a million of women of child-bearing age. The distinction between obligatory and voluntary members makes possible the estimate of the +influence of work continued up to the time of confinement+, because the voluntary members receive the same weekly payments during confinement as the obligatory ones, and, consequently, a woman has no object in joining the voluntary insurance scheme except in order to secure rest before confinement, which they procure for themselves at their own expense and with the loss of their wages. (At that time the compulsory support during time of pregnancy did not exist.) It is to be noted that the voluntary members show ten times as many confinements as the obligatory ones."