in his _Wahlverwandtschaften_, even accepted the influence of paternal impressions on the child. By the beginning of the nineteenth century the majority of physicians were inclined to relegate maternal impressions to the region of superstition. Yet the exceptions were of notable importance. Burdach, when all deductions were made, still found it necessary to retain the belief in maternal impressions, and Von Baer, the founder of embryology, also accepted it, supported by a case, occurring in his own sister, which he was able to investigate before the child's birth. L.W.T. Bischoff, also, while submitting the doctrine to acute criticism, found it impossible to reject maternal impressions absolutely, and he remarked that the number of adherents to the doctrine was showing a tendency to increase rather than diminish. Johannes Müller, the founder of modern physiology in Germany, declared himself against it, and his influence long prevailed; Valentin, Rudolf Wagner, and Emil du Bois-Reymond were on the same side. On the other hand various eminent gynæcologists--Litzmann, Roth, Hennig, etc.--have argued in favor of the reality of maternal impressions.[191] The long conflict of opinion which has taken place over this opinion has still left the matter unsettled. The acutest critics of the ancient belief constantly conclude the discussion with an expression of doubt and uncertainty. Even if the majority of authorities are inclined to reject maternal impressions, the scientific eminence of those who accept them makes a decisive opinion difficult. The arguments against such influence are perfectly sound: (1) it is a primitive belief of unscientific origin; (2) it is impossible to conceive how such influence can operate since there is no nervous connection between mother and child; (3) comparatively few cases have been submitted to severe critical investigation; (4) it is absurd to ascribe developmental defects to influences which arise long after the foetus had assumed its definite shape[192]; (5) in any case the phenomenon must be rare, for William Hunter could not find a coincidence between maternal impressions and foetal marks through a period of several years, and Bischoff found no case in 11,000 deliveries. These statements embody the whole of the argument against maternal impressions, yet it is clear that they do not settle the matter. Edgar, in a manual of obstetrics which is widely regarded as a standard work, states that this is "yet a mooted question."[193] Ballantyne, again, in a discussion of this influence at the Edinburgh Obstetrical Society, summarizing the result of a year's inquiry, concluded that it is still "_sub judice_."[194] In a subsequent discussion of the question he has somewhat modified his opinion, and is inclined to deny that definite impressions on the pregnant woman's mind can cause similar defects in the foetus; they are "accidental coincidences," but he adds that a few of the cases are difficult to explain away.