The theory upheld by Von Baerensprung, that the syphilis of the mother is imparted to her at the moment of impregnation, the disease being impressed upon the fecundated ovule, does not materially conflict with the above views, conception being in either case the essential factor, but in the latter instance the intervention of the foetus itself not being necessary. It has to support it the clinical fact that in those cases where syphilis appears during pregnancy the outbreak of symptoms occurs at about the ninth or tenth week after the date of conception, or a period which closely corresponds to that of the appearance of general symptoms after exposure to ordinary contagion—allowing about three weeks for the so-called incubation of the chancre and six weeks for the secondary incubation.32
32 This has been shown not only by Von Baerensprung (Die Hereditäre Syphilis), but also by Diday, whose observations were intended to prove the possibility of syphilis being derived from the child by the mother—"choc en retour." In 24 cases the period at which the first eruption appeared in the mother averaged sixty-five days after conception; only once did the first signs appear after the fourth month of pregnancy.
It may also be said to be rendered probable by the following line of argument:
Colles's law, which is without exception, demonstrates that every woman who has had a syphilitic child has been herself infected, even if she has had no observable symptoms;33
Cases are recorded, however, in which a woman having given birth to one or more syphilitic children, and therefore herself syphilitic, bears healthy ones in consequence of specific treatment administered to the father before and during the period of conception, she remaining untreated;34
The determining cause, therefore, of the syphilis of the child is not the syphilis of the mother, but the condition of the fecundating germ of the father; and, as a corollary,
The determining cause of the syphilis of mothers in whom the disease follows conception is not by infection from the foetus through the utero-placental circulation35 or otherwise, but is the diseased male procreative cell which becomes blended with the female ovule.36
33 It is obviously no explanation of the law of Colles to say that "it would seem to indicate that the escape of the mother is due to some occult, undiscernible change in her system" (Bumstead and Taylor, op. cit., p. 745).
34 See foot-note, p. 262.
35 On account of the absence of cellular elements in the fluid interchanged.