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��SCIENCE.

��[Vol. v., No. 106.

��TABLE III.

Percentage of the deaf-mute population who are other- wise defective.

�� �Totals.

�Percentage.

�Deaf-matca returned as also blind. . Deaf-mutes returned as also idiotic. Deaf-mutes returned as also insane.

�493

2,339

298

�1.46 6.90 0.88

�Deaf-mutes returned as otherwise de- fective

�2,883 30,905

�8.51

�Deaf-mutes returned as simply deaf.

�91.49

�Total deaf and dumb

�33,878

�100.00

��TABLE IV.

Percentage of the blind population who are otherwise

defective.

��Blind persons returned as also deaf

and dumb

Blind persons returned as also Idiotic, Blind persons returned as also insane,

Blind persons returned as otherwise defective

Blind persons returned as simply blind

Total blind

���TABLE V.

Percentage of the idiotic population who are otherwise

dejective.

��Totals.

��Percentage.

��Idiots returned as also deaf and dumb, Idiots returned as also blind ....

��2,339 1,403

��Idiots returned as otheryrise defective, Idiots returned as simply idiotic. .

��Total Idiots

���TABLE VI.

Percentage of the insane population who are otherwise

defective.

��Percentage.

��Insane persons returned as also deaf and dumb ..........

Insane persons returned as also blind.

Insane persons returned as otherwise defective ^

Insane persons returned as simply in- sane

Total insane

���TABLE VIL

Percentage of the doubly drfective who are also trebly

d^ective.

Of 493 blind deaf-mutes, 217, or 44.02 %, are returned as also

Idiotic. Of 493 blind deafmutes, 30, or 6.09 %, are returned as also insane. Of 2,339 idiotic deaf-mutes, 217, or 9.28 %, are returned as also

blind. Of 298 insane deaf-mutes, 80, or 10.07 %, are returned as ahio

blind. Of 1,403 blind idiots, 217, or 15.47 %, are returned as also deaf

and dumb. Of 558 insane blind persons, 30, or 5.38 %, are returned as also

deaf and dumb.

��The tables seem to indicate that in the case of deafness, blindness, idioc}', and insanity, some correlation exists ; for persons having one of those defects appear more liable to the others than persons normally constituted, and doubl}' defective persons appear to be more liable to be otherwise defective than persons having a single defect. For instance : —

(a) Of 50,155,783 persons in the United States, 246,816, or 0.4921 %,

are defective. (6) Of 246,816 defective persons, 4,597, or 1.86 %, are doubly

defective, (c) Of 4,597 doubly defective persons, 247, or 5.37 %, are trebly

defective.

The results obtained above, I think, merit the consideration of scientific men, and are calculated to throw light upon the subject of correlated defects.

• Although the proportion of the insane who are deaf or blind is abnormally large, the evi- dences of a correlation between insanity and the other defects noted above are not well marked ; but in regard to deafness, blindness, and idiocy, a marked correlation appears to exist.

1 . Deaf-mutes. — There are fourteen and a half times as many blind persons among the deaf aud dumb in proportion to the population as there are in the community at large, and forty -six times as man3' idiotic.

2. Blind. — There are fourteen times as man}' deaf-mutes among the blind in propor- tion to the population as there are in the com- munity at large, and nineteen times as many idiots.

3. Idiotic. — There are forty-three times as many deaf-mutes among the idiotic in propor- tion to the population as there are in the com- munity* at large, and eighteen times as many blind.

The apparent correlation between deafness, blindness, and idioc}', may possibly indicate that in a certain proportion of cases these defects arise from a common cause, perhaps arrested development of the nen^ous system.

It is of course possible that some of the persons returned as ' blind deaf-mutes * may

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