Memoir: Upon the Formation of a Deaf Variety of the Human Race (1883)

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C H A P T E R I . UPON T H E MATERIALS F O E T H E FORMATION O F A D E A F V A R I E T Y O F T H E HUMAN R A C E A T PRESENT EXISTING IN AMERICA. The first diflflculty encountered in the inquiry is that the published reports of our institutions for the deaf and dumb contain very little information bearing upon the subject, but, judging from the questions that are asked of the parents or guardians of the pupils, there must be among the unpublished records of our institutions an immense collection of valuable facts relating to heredity at present inaccessible to the public. Many ot the reports of the institutions contain little more of interest in this connection than a catalogue of the pupils. The mere lists of names, however, become of value by directing attention to the fact that among the pupils who have been admitted to many of our institutions, numerous groups of deaf-mutes are to be found who have the same surname. No one would be surprised by the moderate recurrence of such common names as '* Smith" or "Brown" or "Johnson"—as the recurrences might be accidental, and have no other significance than to indicate the prevalence of these names in the community at large. But can it be acci- dental that there should have been admitted into one institution eleven deaf-mutes of the name of "Lovejoy," seven of the name of "Derby," and six of the name of "Mayhew." What interpreta- tion shall we place upon the fact that groups of deaf mutes are to be found having such names as "Blizzard," "Pahy," "Hulett," "Closson," "Brasher," "Copher," "Gortschalg," &c.? Such names are by no means common in the community at large, and the inference is irresistible that in many cases the recurrences indicate blood-relationship among the pupils. A n examination of a number of institution reports shows that these recurrences are altogether too numerous to be entirely accidental, and we are forced to conclude, (1) that deafness runs in certain families, (2) that these families are very numerous, and (3) that they are to be found in all parts of the United States. The following list of recurring surnames, taken from the 1877 report of the American Asylum for the Education of the Deaf and Dumb (Hartford, Coun.), will show how numerous these recur- rences are among the pupils of our older institutions : 

6 MEMOIRS O F T H E NATIONAL A C A D E M Y O P SCIENCES. T A B L E I.—Recurrence of surnames among 2,106 pupils admitted bettoeen the years 1 8 1 7 and 1 8 7 7 . American Asylum for the education of deaf-mutes, Hartford, Conn Names occurring 25 times Smith. Names occurring 20 times AUen. Names occurring 17 times Brown Names occurring 13 times Campbell, Davis Names occurring 12 times White Names occomng 11 times Clarke, Johnson, Lovejoy Names occurring 10 times Small Names occurring 9 times Fuller, Green, West, Williams, Wood Names occurnng 8 times Bailey, Bartlett, Perkins, Richardson, Rogers, Wright Names occurring 7 times Derby, Jack, Marsh, Martin, Merrill, Thomas Names occurring 6 tunes Berry, Butler, Hawley, Marsh.iU, Mayhew, Morse, O'Brien, Rowe, Rus- sell, Stevens, Swett, Taylor, Tripp Names occurring 5 times Andrews, Ball, Barnard, Blizzard, Chapman, Cook, Curtis, Dennison, Fisk, French, Holmes, Howe, Jackson, Kimball, Meacham, New- combe, Packer, Parkei, Pease, Porter, Reed, Slocum, Sullivan, Til- ton, Webster, Wilson, Young Names occurring 4 times Baker, Bennett, Bigolow, Bishop, Buibee, Chandler, Ellis, Emerson, Fahy, Fishor, Foster, Gilbert, Hammond, Hill, Holt, Hulett, Hull, Jellison, Jones, Kendall, Kennedy, Ladd, Luce Man, Mayberry, Miller, Morgan, O'Neill, Page, Parsons, Prior, Quiun, Robbins, Ryan, Scovell, Stone, Strong, Stuart, Thompson, Turner, Wake field, Ward, Welch, Wells, Wiswell Names occurnng 3 times Abbott, Achesou, Allard, Atkins, Badger, Baldwin, Barnes, Barrett, Blakely, Bliss, Boardwin, Briggs, Bruce, Burnham, Canulon, Car- penter, Carter, Clossen, Clough, Cobb, Cummins, Dauiels, Dennison, Drown, Dudley, Edw.ards, Fish, Frank, Goodrich, Gray, Haley, Haskell, Holden, Hunter, Ingraham, Joidan, LafTerty, Laihbert, Larabee, Livingston, Lombard, Lyman, Macomber, Mahoney, Mann, McCarty, Mitchell, Mocre, MoiTison, Mowiy, Murphy, Nelson, New- ton, Noyes, Osgood, Palmer, Perry, Piatt, Pratt, Prescott, Randall, Reynolds, Robertson, Sage, Sawyer, Sherman, Sloane, Stebbins, Stevenson, Taft, Titcombe, Town, Trask, Wardman, Watson, Wentworth, Wheeler, Whitcomb, Wilkins, Wiuslow, Woodward Names occurring 2 times These are too numerous to be quoted here There are two huudrcd and fourteen of them The following tables show that the pupils referred to above constitute more than 63 per cent, of the total number of pupils admitted:' T A B L E II.—Recurrence of surnames among ilie pupils of the American Asylum for deaf-mutes, Mart- ford, Conn. (1877 Report.) V No of pnpils represented 764 names occur 1 time.. 764 214 names occur 2 times 428 81 names occur 3 times 243 45 names occur 4 times 180 27 names occur 5 times. 135 13 names occur 6 times 78 euamesoccur 7 times. 42 6 names occur 8 (imes. 48 5 names occur 9 times. 45 1 name occurs 10 times. 10 > 3 names occur 11 times 33 1 name occurs 12 times. 12 2 names occur 13 times. 26 1 name occurs 17 times. 17 1 name occurs 20 times. 20 1 name occurs 25 times. 25 1,171 2,1Q6 

THE FOEMATIOF OP A D E A F V A R I E T Y OP T H EHUMAN EAOE. T A B L E III.—Showing recurrence of surnames and liercentages of the whole. (American Asyluru, 1877 Report ) Number of pupils Percentage of tUe Number of sarnames. represented. whole 764 36 i 428 20 3 193 names occur thiee or more times 914 43 4 1,171 2,106 100 0 The Amencan Asylum, at Hartford, Conn., was established in 1817, under the patronage of Congress, as a school to be open to all the deaf-mutes of the United States. A s new centers of instruction sprang up the supply of pupils from the more distant States was practically cut oflF, and the institution is more representative of the New England States than of the whole country. This wUl be obvious from the following table (Table I V ) , which gives a synopsis of 2,109 cases admitted to the asylum before May, 1877, classified according to residence. T A B L E I V . — Classification of pupils in respect to residence. (American Asylum, 1877 Report.) Where from Ifo Whore from No Maine Connecticnt 362 New Hampshire 211 Ctthforma 2 Vermont 233 Pennsylvania 14 / Massacbusetts 731 Maryland 5 Rhode Island 67 NewTork ^4 New Jersey 7 Illinois .' 2 District of Columbia 2 Michigan 1 Virginia 11 Wisconsin 1 North Carolina 4 Ohio 6 South Carolina 19 British Provinces 25 Georgia 27 West Indies 1 Alabama 4 West Virginia 1 Louisiana 1 Texas 1 2.109 Indiana 1 In order to show that the numerous recurrence of surnames is not confined to the deaf-mutes of the New England States nor to the pupils of our oldest institutions, I give a list of recurnng surnames taken from the 1882 report of the Illinois Institution. This institution, although only opened in 1846, is now the largest of its kind in the world, and it may fairly be taken as representative of a large section of country m the West.* T A B L E V.—Recurrence of surnames among 1,620 pupils admitted between the years 1846 and 1882. (Illinois Institution for the Deaf and Dumb, Jacksonville, 111 ) Names occurring 18 times Smith. Names occurring 16 times Brown Names occuiring 10 times Anderson, Miller Names occurring 9 times • Edwards, Wdson Names occurring 8 times Johnson * AB the American Asylum and Illinois Institution may be taken as representative institutions, I present m an appendix a critical analysis of all the cases recorded in the reports referred to. (See Tables A to N, in the appendix ) For this analysis I am indebted to Mr Franck Z Maguire, of Washington, D. C , and I have personally venfaed his results. 

8 MEMOIRS O F T H E NATIONAL A C A D E M Y OP S C I E N C E S . Names occumng 7 tunes: Dayis, Jones Names occurring 6 times- Kelly, Mitchell, Moore, Welch, White, Wilhams, Wright. Names occumng 5 times. Adams, AUen, Clark, Hall, Lee, Long, Stephens, Taylor, Thompson, Wolf. Names occurring 4 times. Bailey, Barnes, Berry, Cox, Gunn, Hams, Hixon, Huffman, Jacohy, James McCUelland, Murphy, Sturgeon, Sullivan, Townsend, Walker. Names occumng 3 tunes Ammons, B.ikor, Ballard, Boyd, Brasher, Brooks, Buckley, Campbell, Carroll, Chamberlain, Conn, Copher, Crawford, Darnell, Doyer, Ford, Fuller, Gibson, Goodner, Goodwin, Gortschalg, Gray, Haqier, Hill, Keil, Kennedy, Laughhn, McFarland, McG<ary, McLean, McNeal, Merrill, Morgan, Neilson, Nichols, Simmonds, Sterling, Stewart, Stout Names occurring 2 times These .are too numerous to be quoted here There aie 150 of them The following tables show that the pupils referred to above constitute more than 41 per cent, of the whole number of pupils admitted: T A B L E VI.—Recurrence of surnames among the pupils of the Illinois Institution for the Deaj and Dumb. (1882 Keport.) No of pnpils represented. 953 names occur 1 time... 953 150 names occur 2 times . 300 39 names occur 3 times 117 16 names occur 4 times.. 64 10 names occur 5 times . 50 7 names occur 6 times.. 42 2 names occur 7 times . 14 8 V 1 name occurs 8 times.. 2 names occur 9 times.. 18 2 names occur 10 times 20 1 name occurs 16 times 16 1 name occurs 18 times 18 1.184 1,620 T A B L E VII.—Recurrence of surnames and percentages of the whole. (Ilhuois Institution, 1882 Report ) Number of pupils Percentage of the Number of surnames. represented •whole 953 58 8 150 names occur twice . 300 18 5 81 names occur three or more times . 367 22 7 1,184 1,620 100.0 The recurrence of numerous surnames among the pupils of very many of our institutions for the deaf aud dumb renders it highly probable that a considerable proportion of the deaf-mutes of the country belong to families containing more than one deaf-mute, and hence possess hereditary tendencies to deafness. The same conclusion is still more forcibly suggested to the mind by a perusal of the few insti- tution reports that record the deaf-mute relatives of the pupils. The following tables (Tables V I I I , I X , X , X I , X I I ) bearing upon this subject have been compiled from the 1877 Eeport of the 

1 T H E POEMATION OP A D E A F V A R I E T Y O F T H E HUMAN R A C E . 9 American Asylum.* They show that of 2,106 pupils admitted to that institution, 693, or nearly 33 per cent, were known to have deaf-mute relatives. The significance of this becomes more apparent when we find that in the majority of these cases the pupils have more than one rela- tive deaf and dumb, while in a few cases as many as fifteen deaf-mute relatives are recorded. T A B L E YllL—Deaf and dumb relatives of the pupils of the Amencan Asylum for Beaf-Mutes, from the 1877 Report. r3 13 Deaf and dumb relatives of pupils Deaf and dumb relatives of pnpils. « Si -a B S 1 great grandfather 31 2 sisters 1 graudtathei 3 3 sisteis 1 giaudfatlier. father, mother .andothei reKitives 1 4 sisters 1 grandfather, father, 3 children, and other rela- 7 1 sister aud 1 cousin tives 1 ] 1 sister, 1 cousin, and 1 uncle 1 graiidf.itber, father, aud brothei 1 1 sistei .and 3 cousins l graudfather, father, and sister 2 i 1 sister, 3 consius, and 1 uncle lather and mother 1 1 S'Ster and 4 cousins father, mother, and l brother 1 1 sister, G cousins, and 1 uncle father, mo^Uoi, aud,3 brothers 1 1 sister and 1 uncle f.,tuoi, mother, and 2 sisters 1 ' 1 Bister aud 1 aunt father, mother, 1 brother, and 1 sister 1 1 sibter, 2 aunts and other relatives father, mother, 2 brothers, and 1 sister 2 1 sislur and other relatives. father, uiothei, 1 brothei, and 2 sisters 1 1 sistoi and 4 other relatives lather, mother, 1 brother, and 5 uncles and 2 1 sister and 14 other relatives aunts 1 1 sister and 7 other relatives father, mother, 1 sister, 1 uncle, and 1 aunt 7 2 sisters and 1 cousin 1 I father, mother, 2 brothers, and 2 uuoles father, mother, 2 sisters, and 1 uncle 1 3 2 sisters aud 2 cousins 2 sisters and 3 cousins father, mother, 1 brother, 1 sister, and 1 uncle 2 sisters and 1 second-cousin father, mother, and 1 cousin 141 J 47 ] brother fathei, son, 1 sister, 2 nephews, and 5 other rela- 1 brother aud 1 sister tives 12 8 1 biother and 2 sisters father, 2 sisters, and other relatives 1 brother and 3 sisters father, 1 brother, and 1 sister 6 2 1 brother, 1 sister, aud 1 cousin father, 1 biother, 1 sister, and 1 cousin 1 brother, 2 sisters, and 2 cousins father, 4 brothers, 1 sister, and 1 cousin 1 1 1 brother, 1 sister, and 3 cousins. father, 3 brothers, 2 sisters, aud 1 coasin 1 brother, 1 sister, and 1 second-coasin mother and 1 biotber 2 4 1 brother, 1 sister, 1 cousin, and 1 uncle mother aud 2 sisters. 1 brother and 1 cousin mother, 1 brother, and 1 sister 1I, 1 1 brother and 3 cousins mother, 1 brothei, 2 sisters, aud 1 cousin >' 1 brothei and 4 cousins mother, 2 brothers, 1 sister, and 1 cousin 1 1 1 brother, 4 cousins, and other relatives 2 mother and 1 uncle 1 brother and 1 aunt 1 mother and 2 uncles 1 2 1 brother and 1 niece 6 1 child 1 brother aud 2 nephews 2 1 child and 1 brother 1 1 1 brother and other relatives 3 1 child and 1 sister 1 brother and 7 other relatives. 1 child and 2 sisters 1 26 1 brother, 1 sister, and 1 second-coasin 1 child and 1 cousin 2 brothei s 2 children and 1 brother 34 11 2 brothers and 1 sister 2 children, 1 brother, and 2 sisters 4 2 brothers and 2 sisters 3 children 2 2 brothers and 1 cousin 3 children and 1 brothei 2 2 brothers, 2 cousins, and 2 uncles 3 childien, I brother, and 1 cousin 1 2 brothers, 1 sister, and 2 cousins 3 children and 1 cousin 1 2 brothers, 2 sisters, 1 uncle, and 1 aunt. 3 children aud other relatives 6 2 brothers, 2 sisters, and 11 other relatives. 4 children. 10 3 brothers 5 children and 1 brother 2 3 brothers and 1 sist«r 5 children and 2 brothers 1 3 brothers and 3 sisters 5 children, 1 brother, and 2 sisters 3 3 brothers, 1 sister, and 2 second-couems. 129 1 sister 4 brothers I *See "The sixty-first annual repoit of the directors and oBBcers of the American Asylum, at Hartford, for the education and instruction of the deaf aud dumb," presented to the asylum May 15, 1877, pp. 42-98 99 A — B E L L 2 

r 10 MEMOIES O F T H E NATIONAL A C A D E M Y OP S C I E N C E S . T A B L E V I I I . — D e a f and dumb relatives of pupils of American Asylum for Deaf-Mutes, &c—Continued. Pupils having deaf and Pupils having deaf and dumb relatives dumb relatives Deaf and dumb relatives of pupils Deaf and dumb relatives of pupils 7 4 brothers and 2 sisters 1 uncle and 1 aunt 1 5 brothers. 1 2 uncles. 2 5 brothers and 1 sister 1 1 niece 22 1 cousin 1 1 nephew 1 1 cousin and 1 uucle 1 2 nephews, 2 nieces, and lother relative 4 2 cousins 1 second-consin 1 2 cousins and 1 aunt 4 2 second-cousiDS 4 3 C01I8IU8 1 1 third-cousin 1 3 cousins and 3 great-uncles 1 I relative 1 3 cousins and 2 uncles 2 relatives 1 3 cousins and 2 other relatives 1 Relatives 2 4 cousins 1 4 rel.itives 2 Cousins 1 4 remote relatives 1 Several cousins 1 6 relatives 3 1 aunt 6 1 uncle b93 Pupils having deaf-mute relatives 693 Pupils recorded as sporadic cases 1,413. Total. 2,106 T A B L E IX.—Deaf-mute relatives of the pupils. (American Asylum for Deaf-Mutes Report for 1877 ) 1 pupil had one or more gieat-graudparents deaf aud dumb 5 pupils had oue or more grandpaieuts deaf aud dumb 47 pupils had one or more paients deaf and dumb 29 pupils had one or more children deaf and dumb 593 pupils had one or more brothers or sisters deaf and dumb 100 pupils had oue oi more cousins de.af and dumb 38 pupils had one or more uncles or auuts deaf and dumb 1 pupil had oue or more great-uncles or aunts deaf and dumb 48 pupils had one or more distant relatives deaf and dumb T A B L E X.—Deaf-mute children of the pupils. (American Asylum for Deaf-Mntes Report for 1877 ) 29 pupils had 1 or more children deaf and dumb 15 pupils had 2 or more children deaf and dumb 13 pupils had 3 or more children deaf and dumb 4 pupils had 4 or more children deaf and dumb 3 pupils had 5 or more children deaf aud dumb T A B L E XI.—Deaf-mvte brothers amd sisters of the pupils. (American Asylum foi Deaf-Mutes Report for 1877 ) 593 pupils had 1 or more brothers and sisters deaf and dumb 271 pupils had 2 or more brothers and sisters deaf and dumb lib pupils had H or more brothrrs and sis'ers deaf nnd dumb 51 pu])ils had 4 or more biothers and sisters deaf and dumb 15 pupils had 5 or more brotbeis and sisters deaf and dumb 11 pupiU had 6 oi more brothers and sisters deat and dumb 

THE FORMATION OP A D E A F V A R I E T Y OP T H E HUMAN RACE. 11 T A B L E XU.—Showing numher of pupils having one or more deaf-mute relatives. (American Asylum for Deaf-Mntcs Report for 1877 ) 693 pupils had l o r more lelatives deaf aud dumb 374 pupils had 2 or more relatives deaf and dumb 224 pupils had 3 01 more rolatnes deaf aud dumb 120 pupils had 4 or more relatives deaf and dumb 65 pupils had 5 or more relatives deaf and dumb 35 pupils had 6 or more relatives deaf and dumb l.T pupils had 7 or more relatives deaf and dumb 9 pupils had 8 01 more relativ es deaf and dumb 4 pupils had 10 01 more relatives deaf and dumb 3 pupils had 15 or more relatives deaf and dumb Without going into detail, the results may be noted of an examination of a few other institution reports* where the deaf-mute relatives are recorded T A B L E X I I I . — P r o p o r t i o n of the deaf and dumb having deaf-mute relatives N u m b e r of Percentage of Total number pupils hav- pupils hav- Institutions ing d e a f- ing d e a f - of pupils mute rela- mute rela- tives tives American Asylum 2,106 693 32 9 New York Institution 1,165 380 32 6 Ohio Institution . . . . 560 166 29 6 Indiaua Institution. . 28J 103 3b 4 Illinois Institution . . 1,620 356 21 7 Texas Institntion . 89 21 .23 6 Total 5,823 1,719 29 5 The above table shows us that out of 5,823 deaf-mutes taken from different parts of the country no less than 1,719, or 29J per cent., were known to have relatives deaf and dumb. I f this proportion holds for the whole country, we must have in the United States about 10,000 deaf-mutes who belong to families containing more than one deaf-mute.t It IS to be feared that the intermarriage of such persons would be attended by calamitous results to their offspring. These are not, however, the only cases m which we would anticipate that the deafness of the parents might be transmitted to the children. The lessons we have learned from the lower animals concerning heredity teach us that a certain physical peculiarity, which may normally make its v_appearance only sporadically here and there, may be perpetuated and rendered hereditary, by suit- able selection, during a number of generations, of those individuals that happen to possess the pecuharity from birth. *The tables rel.atiug to the deaf-mutes of Ohio, Indiana, New York, Texas, and Illinois have been compiled from the following sources 1 Ohio " L i s t o f pupils admitted to the Ohio Asylum previously to Jauuary, 1854 " Amenciin Aunals of the Deaf and Dumb, Vol VI, pp 101-116 2. Indiana " Catalogue of the pupils of the ludiana Institution from its commencement in 1843 to November 1, 1853 " American Annals of the Deaf aud Dumb, Vol VI, pp 162-169 3 New York "List of pupils of the New York Institution, &c , complete from May, 1818, to January, 1854 American Annals ot the Deaf and Dumb, Vol VI, pp 195-2^5 4 Texas " List of pupils in attendance at the Texas Institution (1881^ " See Exhibit A, twenty-fifth annual report of the superinteudeut of the Texas Institution for the Deaf aud Dumb Austin, Tex , November 1, 1881 5 Illinois "List of pupils of the Illinois Institution admitted between 1846 and 18-)2 " Twenty-hrst biennial report of the trustees, superintendent, and treasurer of the Illinois Institution for the Education of the Deal and Dumb Jacksonville, 111 , October 1,1882 t The number is probably greaiei, even exceeding twelve thousand, as will be seen further on. (See Table X V I I ) 

12 MEMOIRS OP T H E NATIONAL A C A D E M Y OP SCIENCES. We have good reason, theretore, to fear that the intermarriage of congenital deaf-mutes, even though the deafness in both cases might be sporadic, would result in many cases in the production of deaf ofl'spriug. I t is important, then, to arrive at some idea of the numbers of the deaf and dumb who are deaf from birth. The Compendium of the Tenth Census of the United States shows us that there were living m this country on tbe 1st of June, 1880, no less than 33,878 deaf mutes, and that "mote than one- half" were congenitnlly deaf.» The proportion can be obtained more exactly from an address delivered in Jacksonville, 111., on the 29th day of August, 1882, before tlie tenth convention of America:i instructors of the deaf and dumb, by the Rev. Fred. H . Wine5<,t who had charge of tlie department of the census relating to the deaf and dumb. Pending the hill publication of the census returns, the statements of Mr. Wines concerning the census of the deaf and dumb must evidently be received as authoritative. I n the address referred to Mr Wines gave the results of an analysis of 22,472 cases from the census, from which it appears that of these deaf-mutes 12,154, or 54.1 per cent., were reported as congenitally deaf, and 10,318, or 45 9 per cent., were stated to have lost their hearing after birth. I f we apply these figures to the total mentioned m the Compendium of the Census (33,878) we find that there are probably 18,328 congenital and 16,550 uon-congenifal deaf-mutes in the United States. Deductions drawn from the breeding of animals would lead us to expect that the congenitally deaf would be more likely than those who became deaf from accidental causes to transmit their defect to their offspring. Another indication pointing in the same direction is to be found m the fact that the proportion of the dc<it and dumb who have deaf-mute relatives is very much greater among the congenital than among the non congenital deaf-mutes The following tables (Tables X I V , X V , and X V I ) have been compiled from the reports of the Amencan institutions for the deaf and dumb already referred to: TABLE XIV. Pupils recorded to have Cause of deafness deaf-mute relatives B I s £ Canse of deafness Name of institution. tl n is •a-o C3 P o American Asylum . . . 1817 1817- 1877 2,106 973 1,040 93 693 552 131 10 New York Institution 1818 1818- 18=)3 1,165 488 432 245 3H0 287 74 19 Ohio Institution . . . 18<!9 1829-1853 560 208 268 84 166 118 32 IG Indiana Institution... 1844 18'4-1853 283 149 124 10 103 72 31 Illinois Institution . . . 1846 1846-1882 1,620 418 947 255 356 194 120 42 Texas Institution 1857 1831 89 26 53 10 21 11 8 2 Total 5,823 2,262 a, 864 697 1,719 1,234 I 396 89 * Compendium of the Tenth Census, Part II, page 1664 tSee Proceedings of the Tenth Convention of American Instructors of the Deaf and Dnrab, Jacksonville, 111 , August, 1882, pp 122-128, published by the Illinois Institution for the Deaf and Dumb, Jacksonville, 111, with the twenty-first biennial report of that Institution 

T H E FORMATION OP A D E A F V A R I E T Y OP T H E H U M A N R A C E . 13 T A B L E XV.—Proportion of tlie non-congenitally deaf who have deaf-mute relatives. Number of Number having Percent.age Institutions. non-coDgenital deaf-mute rel- having deaf-mute deaf-mutes. atives. relatives. I American Asylum 1,040 131 12.6 i New York Institution. 432 74 17.1 I Ohio Institution 268 32 11.9 Indiana Institution . . . 124 31 Illinois Institution 987 120 12.7 Tex.TB Institution 53 8 15.0 Total. 2,864 396 13.8 T A B L E XVI.—Proportion of the congenitally deaf who have deqf-muie relatives. Number Number having Percentage Institutions. of congenitally deaf-mute rel- having deaf-mute deaf pnpils. atives. relatives. American Asylum 973 552 56.7 New York Ins itntion 488 287 58.8 Ohio Institution 208 118 56.7 Inrliaua Institution . . 149 72 48.3 Illinois Institution... 418 194 46.4 Texas Institutiou 26 11 42.3 Total 2,262 1,234 54.5 The above tables (Tables X I V , X V , and X V I ) show that of 2,262 congenital deaf-mutes, more than one-half—or 5i.5 per cent.—had deaf-mute relatives; and that even in the case of those pupils who became deaf from apparently accidental causes, 13.8 per cent, had other members of their families deaf and dumb. I f we apply these results to the total returned by the Tenth Census, we obtain the following figures (Table X V I I ) as a probable approximation to the number of sporadic and non-sporadic cases of deafness among the deaf-mutes of the country. T A B L E ^Yll.r—Estimate of the probable number of sporadic and non-sporadic cases of deafness among the deaf-mutes of the United States in the year 1880. Number who Cause of deafness. have relatives Sporadic cases. Total. deaf and dumb. 9,9.^9 8.339 18,328 Disease or accident 2,146 13,404 15, .550 Total... 12,135 - 21,743 33,878 I f to the estimated number of deaf-mutes who have relatives deaf and dumb we add the pre- sumed number of sporadic cases among the congenital deaf-mutes we-reach a total of 20,474 cases where the deafness would probably tend to become hereditary by intermarriage. But these are 

14 MEMOIRS O F T H E NATIONAL A C A D E M Y O F SCIENCES. not all the cases in which we would anticipate that intermarriage might be productive of deaf off- spring. The late Dr. Harvey L . Peet states, as the result of his researches,* that the hearing brothers and sisters of a deaf-mute are about as liable to have deaf children as the deaf-mute himself I t IS only reasonable to assume that a tendency towards deafness exists in a family containing more than one deaf-mute, so that if hearing persons belonging to such families were to intermarry, or were to marry deaf-mutes—or if a consanguiueous marriage were to take place in such a family— we would not be surprised if some of the offspring should be deaf In addition therejore to the 20,474 deaf-mutes referred to above, we must include the hearing and speaking members of their families before we can form an adequate conception of the numbei of persons who possess a predisposition toioat ds deafness. I t will thus be seen that we have abundant materials in the United States for the formation of a deaf variety of the human race by selection in marriage. 'American Annals of the Deaf aud Dumb, Vol V I , p 235