CXXXVIII BOWMAN LECTURE. 



VI. Leber's disease. 



(a) Abstracts of all the cases with figures., except Case-figs. 45- 



52 placed in the text of the lecture. 

 (I) References to cases or figures in a, illustrating various 



features of the disease discussed in the lecture. 

 VII. Nystagmus. 



(a) Albinism section : (1) Case-figs. 53, 56, 57, 58, 59, 60. 



(2) Various references to published cases 

 and the following new cases, Figs. 

 " 182, 183, 184, and 188. 



(6) Day-blindness section : Various references to cases and Case- 

 fig. 185. 



(c) Unclassed nystagmus ; references to places of publication. 

 VIII. Cornea, Case-figs. 65-69. List of principal publications. 

 IX. Abbreviations for titles of periodical publications. 



APPENDIX I. 



FREQUENCY TABLES. 



Data upon which the Statements at p. Ixix et seq. of the Lecture as to the 

 Relative Numbers of Normal and Diseased are based. 



Only those sibships (childships) have been used that Avere either 

 known or judged on good grounds to be complete as to numbers and sex 

 record ; only those in which (with one single exception) the youngest 

 member was old enough to be siisceptible to the disease in question ; and 

 only those in which either one or more of the siblings or one of the 

 parents of the sibship was affected. Therefore, from the childships 

 selected all members are excluded who died before the usually vulnerable 

 age and all still-births and miscarriages. I am well aware that the 

 omission of these items might lead to inferences that in the present 

 state of our knowledge are unwarranted : for whether the numbers here 

 given from human data do or do not agree with Mendelian requirements 

 we are certainly not at present entitled either to affirm or deny that the 

 proportions of normal and diseased would have been the same if all the 

 conceptions had lived to the susceptible age. My object has been only 

 to ascertain, on a somewhat larger scale than has been attempted before, 

 how far the available numbers, as they stand, do or do not fit with 

 Mendelian expectation as based upon experimental breeding. 



In such diseases as post-natal cataract, very small lamellar or discoid 

 cataract, and even retinitis pigmentosa, the proportion of affected to 

 normal is almost certain to be more or less too low, for in these diseases, 

 and especially post-natal in cataract, the earliest stages of the malady 

 may pass iindiscovered unless the eyes of every member be examined a 

 condition that can seldom be fulfilled. 



When descent is continuous every completed sibship in which the 

 disease occurs is counted, and every sibship of which either parent is 

 affected, whether any of the children are so or not. When descent is 

 discontinuous only the sibships showing the disease can be used. 



