AS TO THE HEREDITY OF ACQTJIKED CONDITIONS. 501 



at the subjects of increase and diminution of tlie incisors *, did 

 not meet with any cases which bore out this theory ; but this, of 

 course, does not prove that in certain cases it may not be true. If 

 so, it strengthens the argument in favour of precursory conditions 

 for some cases of palatal and labial defect. The second example 

 is quoted by Page f from Boehm J. A woman had " beautiful 

 blue eyes, delicate white skin, and, what is especially characteristic 

 of a tendency to albinism, colourless eyebrows and eyelashes." 

 Her daughter had white eyebrows, lashes, and skin, and great 

 irritability to light, whilst the grand-daughter had internal 

 strabismus and nystagmus, and hair " originally as white as well- 

 bleached linen." Some other cases of a cumulative nature are 

 given in my previous paper. It seems to me possible that these 

 cases are due to an original flaw in the nervous system. "Whether 

 this flaw is due to a failure of development consequent upon 

 conditions inherent in the germ, or upon the slow eff"ect of some 

 condition connected with the environment acting upon several 

 generations, as was suggested by Coles when writing about cleft- 

 palate, and as Weismann seems to hint may be the case in the 

 essay referred to above, must at present and for a long time 

 remain an open question. But in either case the nervous defect 

 would precede the more obvious one, and may in an earlier gene- 

 ration exhibit its effects in a manner perhaps never recognized, 

 by slight trophic disturbances and the like. Descending further 

 and gathering force as it descends, under favourable circumstances, 

 the conditions met with, at times, in the parents of children with 

 cleft-palate or whatever the defect may be will be reached, and 

 in the next generation or in one closely succeeding the full defect 

 may appear, the precursory conditions having been quite un- 

 noticed. I do not wish it to be understood that I am arguing 

 either that all malformations have a nervous origin or that the 

 chain of events which I have suggested, or one of a similar nature, 

 occurs in all cases ; what I desire to point out is that in some 

 cases, and perhaps in more than at present we have any idea of, such 

 precursory conditions may be capable, by diligent inquiry, of 

 demonstration. In these facts we also may, I think, find a clue 

 to the real significance of the much-abused word "tendency." 

 This word, and especially in its relation to the so-called here- 



* Joum. of Anat. and Phys. vol. xxi. p. 84. t ' Lancet,' Aug. 8, 1874. 

 I Der Nystagmus unci dessen Heilung. 



