78 Inhe7'ita7ice of Deformity known as Split-Foot or Lobster-Claw 
families in which mere syndactyly or Polydactyly occurs, or again in which club-foot 
alone is inherited ? It appears to me that in a case like the present we cannot 
possibly speak of the presence or absence of a unit character, there must be an 
inertia or weakening of some development-controlling determinant. I will not 
venture to call it an absence of such a determinant, because its range varies so 
widely from individual to individual. If we use the word absence we must make 
the full control depend on the presence of a large number of units, and there must 
be — as for example in the reducing division^ — ^some process by which a random 
number of these are cast out. Even with this interpretation we are really thrown 
back on quantitative degrees in the controlling factor. These control units cannot 
be specific, for if they were associated with special bones, it is not easy to under- 
stand how a bone occurring in parent and grandparent* could disappear in the 
zygote resulting from a normal union. The problem has been forced on me 
recently from the practical side in studying cases of human degeneracy with 
correlated defects, and although I have thought over it carefully I ca.n see no 
daylight theoretically in these questions of correlated physical or mental defects 
— defects having a considerable range of variation, but peculiar to certain stocks 
— except from the assumption of development-controlling units or determinants. 
These determinants may be more or less definitely associated with certain 
portions of the body — hands and feet, or eyes for example — but the total number 
rather than any specific character of each must determine in every individual case 
the extent of defective development. Whatever the modus may be, i.e. whether 
the deterrainantal system be quantitatively continuous or consist of discrete units, 
I venture to suggest that it is rather in the direction of inertness in controlling 
determinants than in the hypothesis of a definite allelomorphic character in the 
Mendelian sense that we must seek for light on the inheritance of physical or 
mental degeneracy or deformity in man. The complexity and variety of the 
deformity in many of these cases is too great for us to attribute it to a single 
allelomorph, and there is thus no obvious reason for anticipating a simple 
Mendelian ratio. 
(7) On the subjects of my present study a few general remarks may be made. 
They show remarkable aptitude in the use of their misshapen hands. At school 
the children hold their own with normal scholars in writing, drawing, and even 
needlework. The family rather resent anything in the shape of pity. One of its 
men expressed himself as follows : " Bless 'e, sir, the kids don't mind it. They 
never had the use o' fingers and toes, and so they never misses 'em." One of the 
girls with the 5th digit only on each hand is learning dressmaking as a pursuit. 
In Messrs Lewis and Embleton's family the gait appears to be normalf, but I 
should hardly say that this describes those members of the present family that 
I have seen. One who has long been acquainted with them writes : 
* E.g. the first digit of the foot existing in III. 21 and II. 2 disappears in the offspring of a marriage 
of III. 21 with a normal, as in IV. 21. 
t Biometiihi, Vol. vi. p. 28. 
