AS TO THE HEERDETY OF ACQUIRED COTfDITIQNa. 487 



fact the only note 0:1 the subject which I have been able to find 

 is a remark by Priestley that Spath in nineteen cases in which 

 calcareous concretions were present in the placenta, found one 

 of congenital rachitis, one of spina bifida with hydrocephalus, and 

 one of slight hydrocephalus. On which Priestley remarks that 

 " the presence of calcareous deposits, in the placenta, therefore 

 seems associated with some pathological conditions unfavourable 

 to the welfare of the child, although the adverse influence does 

 not proceed far enough in most cases to extinguish life." It is 

 to be noted that the first and last of the cases mentioned are cases 

 of foetal disease, and that the second one, seeing that hydrocephalus 

 was also present, almost certainly comes under the same category. 

 As in the case of parental nutrition, it seems more likely that 

 disease of the placenta would produce general rather than special 

 effects upon the foetus. 



Section IV. — On the possible Nervous Origin" of 

 CERTAIN Malformations. 



Part 1. — Affections of a possibhj Trophic Nature. 



Under this heading I desire to discuss the possibility of an 

 inefficient action of tbe nerves during the development of the 

 embryo being a cause of malformations. I have used the word 

 " trophic," not because it quite expresses what I mean, but be- 

 cause I know of no better term. The point I wish to raise is, 

 whether the trophic nerves or other nerves allied to them have 

 not a potent action in directing the development of the embryo, 

 and whether a failure for any reason on the part of these nerves 

 to do their work may not be followed by certain malformations,, 

 In considering this question, it will first be advisable to learn what 

 effects follow upon trophic failure iu post-uterine life. Landois 

 and Stirling * say in this connection, that the nutritive changes 

 which follow in the eye, upon section of the ophthalmic division 

 of the fifth nerve, are best explained by the theory of trophic 

 fibres, whose centre is the G-asserian ganglion, and they proceed 

 to state : — " The trophic disturbances which sometimes accompany 

 alfections of the trigeminus are particularly interesting. They 



* Text-Book of Human Pbysiology, toI. ii. p. 796. 



