E. Schuster 
471 
general do to hearing persons, we work on the supposition that this rehition is 
borne by deaf children to hearing children ; then as we are dealing with 13,489 
plus 506 = 13,995 deaf children, these must occur among a total number of 
21,236,722 children, of whom 21,222,727 are hearing, and as 4878 have deaf 
fathers, 21,217,849 would have normal fethers, and in this way Table IV. may be 
constructed. 
TABLE V. 
Fathers. 
ren. 
Deaf 
Hearing 
Hearing 
4878 
8,159,692 
Q 
Deaf 
506 
4878 
// =/• =3-212070 
7/=A'= -002294 
r = -62 
TABLE VI. 
Fathers. 
Deaf 
Hearing 
Hearing 
Deaf. 
3519 
132 
5,533,042 
3519 
h =k =3 '212070 
H=K= -002294 
r =-46 
Tables III. and IV. thus combine the information derived from Tables I. and 
II. In Table II. the assumption is made that the proportion of deaf to hearing 
fathers is that of the general population, and in Table IV. a similar assumption is 
made for the children. Tables V. and VI. assume that both with regard to fathers 
and children this is the case. If this assumption be made then the table must be 
a symmetrical one, and as one cannot get a symmetrical table by combining the 
two sources of information, one has to construct a separate table out of each. In 
Table V. the information from Table I. only is used, and in Table VI. that from 
Table II. 
Tables VII., VIII. , IX. and X. were made for mothers in exactly the same way 
as III., IV., V. and VI. were for the fathers. In Table XL the values of the 
con-elation coefficients for each of these eight tables are set down. It will be 
TABLE VII. 
Mothers. 
Q 
Deaf 
Hearing 
Hearing 
Deaf 
4632 
469 
7,722,294 
13,121 
li =2-919020 
//= -005632 
k =3-212070 
/vr= -002294 
/• = -51 
