Thus we find that, in 201 instances of relationship be tween the parents of mutes, 85 were in the degree of first cousins, G3 in that of second, 32 in that of third, 7 in that of fourth, and in 14 they were more remotely related. Dr Bondin, at a meeting of the Academy of Sciences, Paris, noticed the following striking result of such unions : "Two brothers in perfect health, and well constituted men, had married two sisters, their cousin s-german. The elder brother has had several children, one of whom is deaf and dumb. The other brother has had six children, the first, third, and fifth of whom can hear, while the second, fourth, and probably the sixth (an infant) are deaf and dumb." The report of Dr S. M. Bemiss of Louisville, Kentucky, to the American Medical Association on the subject of the influence of marriages of consanguinity on offspring -and re cords the following results of 833 such marriages : Of the 3942 children of those marriages 1134 were defective in one way or another, viz., deaf and dumb, 145 ; blind, 85 ; idiotic, 308; insane, 38; epileptic, 60; scrofulous, 300; and deformed, 98; 883 died young; and the writer concludes by remarking, "I feel satisfied, however, that my research gave me authority to assume that over 10 per cent, of the deaf and dumb, and over 5 per cent, of the blind, and nearly 15 per cent, of the idiotic, in our State institutions for subjects of those defects, and throughout the countiy at large, are the offspring of kindred parents, or of parents themselves the descendants of blood intermarriages. Another great cause of deafness is hereditary transmis sion. " It has clearly been ascertained," says Dr Harvey (On the Ear}, " that the most common cause is a strumous and delicate habit of body, generally hereditary." The subjoined table from the census returns for Ireland in 1871 proves that deaf-muteism is often transmitted by hereditary taint or family peculiarity. The table is divided into two sections, the first showing where the disease is transmitted by the father, the second by the mother. Mute relations on Father s side. No. of Deaf Mutes in each family. Great- Grandfather. Great- Grandmother. Grandfather. Grandmother. Granduncle. Grandaunt. 13 _0 c a +s c < _c 3 3 3 H One Two 1 1 1 5 o 5 4 12 4 8 1 59 16 93 96 Three.... o 1 1 2 10 16 Four 1 1 9 Five 2 2 139 Mute relations on Mother s side. No. of Deaf | o ij c Mutes in eacli family 3
3 a a a a 13 Mother. Uncle. Aunt. Cousin. Total
O O .One 2 3 2 9 6 12 33 67
- Two
3 9 2 3 23 33 Three 1 1 7 9 Four 2 1 3 Five 2 2 114 - The Commissioners Report is as follows : "Although it has been shown that muteism is transmitted by hereditary taint, yet it very seldom descends directly from the parent to the offspring, which is manifest from the following results of the inquiry made respecting the marriage state of the congenitally ^"" f After a minute investigation of this subject, we find 115 deaf. instances, 77 males and 38 females, of the marriages of congenital deaf mutes where either one or both parties were affected. In 81 instances we ascertained that only one of the parties was congenitally deaf, and that 264 children, none of whom were deaf and dumb, ri-sulted from 67 such marriages; in the remaining 14 instances there was no issue. We find four instances of the marriage of a congenital deaf mute with an acquired deaf mute, from three of which 7 children resulted, one of whom was deaf and dumb. There were 13 instances of the intermarriage of persons both of whom were deaf and dumb, and from 12 of these marriages 44 children resulted, of whom only one was deaf and dumb, a"nd another was deaf only. The grand-parents of the former on the mother s side, and a grand-uncle of the father s, were also deaf and dumb. Of 315 children resulting from 87 of the afore-mentioned marriages, only two were deaf and dumb, and one deaf only. In a case of the intermarriage of congenital deaf mutes, although the husband s parents were second cousins and the wife s also related, and her sister deaf and dumb, yet none of the 8 children resulting from the marriage were in any way afflicted. The Principal of the New York Institution says, "We can show that it is much the most common for the children of deaf and dumb parents to possess the faculties of which their parents are deprived ; still, although the offspring may not be defective, they may likely inherit that peculiar taint of constitution by which the disease will be transmitted to future generations, which is so often the c,asc." Mr Turner, in a paper on Hereditary Deafness, gives the following table : No. of No. of Class. Parents. Families. Children Deaf. Children Hearing. Total. 1 One hearing and one congenitally deaf 30 15 77 92 2 One incidentally and one congenitally deaf 56 6 120 126 3 Both congenitally deaf.... 24 17 40 57. 110 38 237 275 From this it appears that in 86 families with one parent a congenital deaf mute there were 218 children, of whom 21 were deaf and dumb, or about one-tenth of the whole. In the 24 families with both parents congenital deaf mutes there were 57 children, of whom 17 were deaf and dumb, or about one-third of the whole. The proportion of deaf- mute children of parents both congenitally deaf is thus more than three times greater than of parents only one of whom is congenitally deaf. The subjoined table shows the proportion of the families, constituted as above, who had deaf-mute children in them : Class. Parents. Families. Families- 1 2 3 One hearing and one ) congenitally deaf ... i One incidentally and one congenitally deaf Both congenitally deaf.. 30 24
One or more deaf
I and dumb in 5 1 The proportion of families having one congenitally deaf parent, with at least one deaf-mute child, is about one-tenth of the whole, while the proportion of the families having both parents congenitally deaf with a deaf-mute child or children is more than one-third of the whole. The above tables show the amount of deafness transmitted by the marriage of one congenitally deaf with one hearing person. The cases of deafness resulting therefrom are only one- tenth of the whole, whereas those from the intermarriage of deaf mutes are about one third. Similar results could be obtained from reports of many of the institutions, but from what has already been stated on this cause of deafness, it appears that, while there is sufficient reason to justify the prohibition of the intermarriage of deaf mutes, the excep tional cases of deaf mute offspring as the result of unions of deaf mutes with hearing persons would not justify inter ference in such marriages.
History of Instruction.—In early times, it was an opinion maintained, even by philosophers, that the education of tho deaf and dumb was not possible. It was then believed that language could only be acquired through the medium of the ear. The couplet of Lucretius is well known
