BOWMAN LECTURE. CXI 



one of Leber's earliest cases (1871), 3 siblings were 

 attacked and all recovered ; and in a case of my 

 own 2 cousins recovered out of 4 attacked. In the 

 recovered cases many different lines of treatment had 

 been tried and we cannot be sure that any of them had 

 much effect. A very important feature in these cases 

 is the length of time that may elapse before notice- 

 able improvement of sight begins, often 12 or 18 months, 

 and, in one case, if we can believe the history, as 

 much as 3 years. This possibility of considerable delay 

 in recovery should lead to a more hopeful prognosis 

 being given in future cases; one can, indeed, hardly 

 doubt that the list of favourable results would have been 

 longer had cases been more frequently followed up. 

 Probably some of the t( astonishing cures" of long- 

 standing " blindness " of which we hear from time to time 

 may have been examples of delayed recovery from this 

 disease. 



We shall probably be right in attributing certain cases 

 that individually resemble the type but are without family 

 history of the disease to the same essential cause, what- 

 ever that may be. Such cases, sometimes diagnosed as 

 tobacco amblyopia, do not improve on ceasing to smoke 

 and sometimes show contraction of fields as well as central 

 defect. Interesting communications on such, possibly 

 borderland, cases have been made by Lawford, and 

 Edgar Brown. * 



There is a tendency to anticipation in Leber's disease, 

 both in successive generations and to a less marked 

 degree in successive births in the same sibship ; but 

 the phenomenon is not so pronounced as it is in 

 successive generations affected by glaucoma or by senile 

 cataract. 



Anticipation in successive generations was shown in 14 



pedigrees out of 31 that gave the necessary information, 



the difference between ages of onset in the elder and 



younger generation being from 15 to 25 years. In 11 



* T.O.8., x, 1890, p. 166. 



