tism. Furthermore 42.1 per cent of the deaf whose
parents were cousins were congenitally deaf, while this was true of
but 15 per cent of those whose parents were unrelated.

TABLE XXVIII.
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| | |
| | Consanguinty |
| | of Parents. | Per cent.
| |--------------------|-----------------
| | | | | | |
Cause of Deafness. | | | Not | Not | | Not | Not
|Total.|Cous- |Cous- | Sta- |Cous-|Cous-| Sta-
| | ins. | ins. | ted. | ins.| ins.| ted.
---------------------------|------|------|------|------|-----|-----|-----
| | | | | | |
Total |89,287| 4,065|75,530| 9,692| 4.5| 84.6| 10.9
---------------------------|------|------|------|------|-----|-----|-----
Affections of external ear | 871| 29| 760| 82| 3.3| 87.3| 9.4
Affections of middle ear |34,801| 1,238|30,824| 2,739| 3.5| 88.6| 7.9
Affections of internal ear |12,295| 343|11,121| 831| 2.8| 90.4| 6.8
Unclassified |31,205| 2,183|25,281| 3,741| 7.0| 81.0| 12.0
Unknown |10,115| 272| 7,544| 2,299| 2.7| 74.6| 22.7
| | | | | | |
Scarlet fever | 7,424| 285| 6,647| 492| 3.9| 89.5| 6.6
Disease of ear | 4,210| 222| 3,683| 305| 5.3| 87.5| 7.2
Catarrh |11,702| 304|10,450| 948| 2.6| 89.3| 8.1
Colds | 3,074| 81| 2,666| 327| 2.6| 86.7| 10.7
Meningitis | 3,991| 83| 3,741| 167| 2.1| 93.7| 4.2
Old age | 3,361| 38| 2,369| 954| 1.1| 70.5| 28.4
Military service | 3,242| 40| 2,897| 305| 1.2| 89.4| 9.4
Congenital |14,472| 1,710|11,322| 1,440| 11.8| 78.2| 10.0
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But on the other hand, 53.4 per cent of the deaf whose parents were
cousins had deaf relatives of the (a) and (b) groups, while of those
whose parents were not cousins, only 29.9 per cent in these groups had
deaf relatives. In Table X