500 PEOr. B. C. A. WINDLE ON TEBATOLOGICAL EVIDENCE 



of an acquired defect to account for it. But it is a question 

 whether an explanation such as this can be held to account for 

 all the cases of hereditary myopia. In his essay, however, 

 " On the Supposed Botanical Proofs of the Transmission of 

 Acquired Characters"*, the autlior seems to admit a modi- 

 fication of his views as first expressed, which are of great im- 

 portance in connection with the question of the inheritance of 

 the group of defects at present under consideration. Dr. Mivart 

 in reviewing these essays f niakes the following comment on this 

 modification : — " Although these last two essays are intended to 

 show that acquired characters cannot be inherited, they yet seem 

 to us to show that to a certain extent, and in a certain sense, they 

 may be inherited. We have no desire to contend that they are 

 heritable to any large extent, and we have always afiirmed that 

 mutilations can at the most be very rarely inherited, and long 

 ago referred to obvious proofs that so it must be J. But Pro- 

 fessor Weismann here certainly makes some admissions with 

 respect to the cumulative effect of a changed environment on the 

 germ-plasm of organisms, which contradict his previous assertions 

 that only unicellular creatures can be thus modified. But if such 

 a cumulative effect does exist, then, if sufficient time be allowed 

 (and Darwinians are prodigal of time), a modified Lamarckism 

 reappears ! " It is possible that in the direction thus indicated 

 an explanation may yet be found for some of these conditions. 

 But the whole subject, so far as the eye-defects are concerned, 

 wants working out thoroughly by practical ophthalmologists. 



(5) There are certain points which should be noted, since they 

 seem to indicate the gradual rise and development of a malforma- 

 tion. I will mention two examples. The first is that of the pre- 

 cursory conditions, so to speak, of cleft-palate and hare-lip which 

 were mentioned when that subject was under consideration ; these 

 are of great interest. Again, in connection with the same subject, 

 it should be mentioned that Lucas § has published observations 

 which lead him to conclude that an absence of incisors in a parent 

 is premonitory of cleft-palate or hare-lip in the children, and 

 he has given several cases in support of this theory. I am bound 

 to say that my colleague Mr. Humphreys and myself, when working 



* lb. p. 413. t Dub. Eeview, 1889, p. 269. 



t Genesis of Species, 2nd ed. p. 242. 



§ Brit. Med. Journ., Dec. 3, 1887, p. 1212. 



