LXXII BOWMAN LECTURE. 



once become apparent, i. e. dominant, if it came under 

 the action of the supposed transforming influence. 



I now leave these crude speculations and come to the 

 safer ground of observation. 



Anticipation in hereditary disease means the manifesta- 

 tion of the morbid change at an earlier age in each 

 successor, either in members of each succeeding generation 

 as a whole, or in successively born children of one 

 parentage. Bowman was one of the first to notice antici- 

 pation in successive generations in hereditary acquired 

 cataract,"* and examples. of the phenomenon will be quoted 

 later. It is only seen in some of the families, and we 

 do not yet know in what proportion of them. 



Anticipation in generations is also a marked feature 

 in hereditary glaucoma, but the material hitherto collected 

 is smaller than for cataract. 



Anticipation is also seen fairly well marked in connection 

 with Leber's disease, both in successive generations and 

 successively born siblings. 



Anticipation is not known to occur in retinitis pigmen- 

 tosa, and I believe has not been proved in the now well- 

 known hereditary reticular and nodular keratitis. 



This anticipation in heredity is by no means peculiar 

 to diseases affecting the eye. It appears to occur in 

 phthisis,t and is certainly sometimes met with in heredi- 

 tary diabetes (Fig. 7),J and hereditary jaundice with 

 enlarged spleen (Figs. 8 and 9); also in at least one 

 * Bowman communicated these observations to Darwin, who incorpo- 

 rated them in his chapters on "Inheritance" in Animals and Plants 

 under Domestication, i, p. 453, and ii, p. 56 (1868). They do not seem 

 to have been published in any other form. 



t Pollock, J. E., Medical Handbook of Life Assurance, 4th edition, 1895. 

 Karl Pearson, A First Study of the Statistics of Pulmonary Tuberculosis, 

 1907. (Drapers' Company Research Memoirs : Studies in National 

 Deterioration, ii.) 



J The ages at death are given in Fig. 7 (unpublished case, E. N.), but 

 they could not be conveniently inserted in Figs. 8, 9 and 10. 



Figs. 8 and 9 are constructed from the paper, " Some Cases showing 

 Hereditary Enlargement of the Spleen," by Claude Wilson, Clin. Soc. 

 Trans., xxiii, 162 (1890), and xxvi, 163 (1893). 



