72 Inheritance of Deformity known as Split-Foot or Lobster-Claw 
The amount of material here is not very great, but, as far as it goes, it does not 
support the conclusion that for the tainted families the abnormal members are 
relative to the normal fewer in number. It seems rather to indicate that in the 
last generations the abnormal have been twice as numerous as the normal. My 
data are, however, far less numerous than Messrs Lewis and Embleton's. Leaving 
out their two doubtful cases, I find {Biometrika, Vol. vi. Plate I) that they have 
32 normal to 43 abnormal members in the families of their stock with deformed 
parents. I shall confine my attention to their stock and my stock, because I feel 
in my own case the confidence of the personal collector, and am sure that a 
number of individuals have not been omitted or wrongly classed ; and because I 
realise in their case also that Messrs Lewis and Embleton have examined their 
stock with the special view of testing definite ratios. The fixmilies of other 
observers may have been carefully worked out, but the importance of complete 
enumeration has only been recognised since it has become desirable to test 
Mendelian theory. 
Examining the data from the statistical standpoint, I draw attention in the 
first place to the first family of the third generation. This family should approxi- 
mate to o normal to 3 deformed, but every member born was deformed. The odds 
against a run of six deformed ai'e 63 to 1, if the chances of normality and of 
lobster-claw are e(|ual. The odds against a deviation as great as 25 to 14 from a 
ratio of equality are 14 to 1 ; the odds against Messrs Lewis and Embleton's ratio 
of 43 to 32 are about 9 to 1 ; the odds against such an excess as is represented 
by our combined results 68 to 46, — a ratio corresponding to 3 to 2 instead of 
1 to 1, — are more than 49 to 1. Now this excess of the abnormal in any de- 
formity like the present ought to be admitted, if it actually exists, for it is not 
only opposed to simple Mendelism, but its bearing on Eugenics is of the greatest 
importance. While I have found the like excess in other cases, it does not appear 
to be true for all deformities. Thus, from the pedigree plate in Mr Nettleship's 
admirable paper on Night Blindness*, I deduce the following results: 
Abnormal 
Normal 
Generation 
III. 
10 
6 
Generation 
IV. 
15 
43 
Generation 
V. 
26 
29 
Generation 
VI. 
30 
51 
Generation 
VII. 
27 
55 
Generation 
VIII. 
14 
36 
Generation 
IX. 
9 
11 
Totals 
131 
231 
Ophthalmoloyical Society's Transactions, Vol. xxvii. pp. 269-291. 
