When the mother is infected at the time of conception the child is always syphilitic. If the mother is infected early in pregnancy the child is almost always infected. If she is infected late in pregnancy the child may escape infection. Men with tertiary syphilis have begotten children without, to all clinical appearance, inoculating the wife. In such a case the mother may nurse the child with safety to herself, but the child will infect a wet nurse other than its own mother, and in very rare instances mothers in this condition have been floridly infected. The condition here described is called Colles's Law.[152] The doctrine of Colles's Law has fallen into disuse because we can now demonstrate by the Wassermann reaction that almost all apparently healthy mothers of this class are in reality infected. The term now used is "Syphilis by Conception."[153] The virus passes through the fetal placenta to the mother, although immunizing substances are held back by the placenta. A fetus cannot make immunizing bodies before its eighth month, and on that account the earlier the fetus is infected, the more likely it is to die. Recently, however, some scanty testimony has been collected which sustains Colles's Law in a few cases. Ledermann reported three cases, and Nonne others, in which the wives of men with tabes or paralysis bore syphilitic children and yet never responded positively themselves to the Wassermann test, or showed any symptoms suggesting syphilis. To this list Kroon[154] adds a case corresponding fully to the requirements of Colles's Law. A woman of twenty-eight years who had had eight abortions was delivered of a child with undoubted congenital syphilis. The child's father had been infected with syphilis twelve years before. The woman showed no signs of syphilis, two Wassermann tests were negative, and she nursed the child without injury to herself. [152] From Abraham Colles, Dublin, 1837. [153] Wolff, 1879. [154] _Nederlandisch Tijdschrift voor Geneeskunde_, i, 9. Should the husband have florid primary or secondary syphilis, and infect his wife at impregnation, abortion is the rule. The commonest cases are those where the husband has been treated for syphilis more or less thoroughly before marriage. Even if at the time of impregnation the husband has no apparent infective lesion, the child is usually syphilitic, or it may show signs of the disease later in life. Ibsen's _Ghosts_ is founded on a case like this. If the syphilis is recent, or uncured, the child dies, macerates, and is expelled. These conditions recur in pregnancy after pregnancy, until the virus is removed by time or drugs. As the nucleus of the spermatozoön is too small to carry the spirochete of syphilis, the infection is through the semen in a manner not yet clear to us.