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

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Chaptee v. tJPON THE GROWTH OF THE DEAF-MUTE POPULATION The full returns of tbe 1880 census, so far as regards the deaf and dunib, have not yet been published; but, as stated before, Eev. Fredeiick H Wines, who had charge of this department of the census, presented to the tenth convention of American instructors of the deaf and dumb the results of an analysis of 22,472 cases of deaf-inntes reported in the census leturus The tables presented by Mr. Wines have been reproduced in the Appendix. (See Tables N, O, P, Q.) It will be observed that the cases are classified accoidmg to the period when deafness occurred and according to the cause of deafness (whether congenital or not). I have rearranged these cases into decades, so as to correspond with the classification of the pupils of the American Asylum and Illinois Institution, and have represented the results graphically in the following diagram: aoo 800 600 600 400 •aoo 200 \ zoo \ 3000 \\ 3000 • 800 \ BOO \ 600 600 \ 400 \ 400 \ 200 \ ZOO \ iooo ZOOO aoo 800 600 600 400 4O0 zoo ZOO 1000 1000 600 800 600 600 400 400 zoo - ZOO 1 o s ? 1 1 1 1 i 1 1 1 1 R 1 1! ,ll a * c> M 1 i 1 M «1 "1 "0 1 1 °5 F I G 8—Belation between tbn congcDital and non congenital doaf mutes of the coiinlrr, according to the Kov Fied H Wines Tbe congenital deaf mutes are indicated by the dark line, the non congenital, b\ tbe hgbt line 35 

36 MliMOIRS O F T H E N A T I O N A L A C A D E M Y O F S C I E N C E S . The ordmates of the curves represent, respectively, the number of congenital and non-con genital deaf-mutes who became deaf in the decades indicated by the abscissae. I n the case of the congenital deaf-mutes the ordmates also represent the number who were born m the decades given, but this IS not true of the non-congenitals. I t will be observed that the number of deaf-mutes re- turned who became deaf in the last decade, 1871-'80, is less than the number who became deat in the preceding decade. This does not necessaril^\ mean that the number actually was less, but more probably indicates that the returns for the last decade are imperfect. Mr. Wines says that " I n proportion to the degree ot their youth the younger deaf-mutes are not enumerated Fewer deaf- mutes who are babes in arms are enumerated tlian at the age of three years, and fewer at three J ears than at seven. The apparent maximum at seven is not the actual maximum; the actual maximum is at some younger age not yet ascertained." In the above diagram those portions of the curves that are believed to be unreliable from this cause are indicated by dotted lines I t will be observed that among the older deaf mutes the congenitals are more numerous than the non congenitals; whereas among the younger the reverse appears to be the case. There is no apparent diminution in the numbers of the congenitally deaf born of late years; and the reversal of the relation between the two classes must be attiibuted to an abnormal increase in the number of those who became deaf from disease or accident. It looks as i f a wave of deafness-producing disease had swept over the continent about the time of the late civil war. 80 ^ 80 SO neon un nstctu turn . eo 40 /i 40 / 20 • ) 20 1 300 1 300 1 \ 80 1 80 1 SO SO 11 40 1 1 40 20 • \ 20 SOO \ 200 \ SO \ \ 80 \ SO y \ SO \ \ 40 is / / 40 1\ \ 29 / \ \ \ SO / \ \ \ WO 300 1/ \ \ \ SO \ SO \ SO \ eo \ 40 » 40 eo so 11 1 f 1\ 11 f 1 1 f ! f 1 1 OS Kt f f i T 1 1 1 1 1 •a 1 1 1 1 1 1 «> 1 1 1 <o 1 1 1 1 11 i-r n ,11 N ?! S 1 1 1 1 2 1 1 ^1 05 8 'ti Y\c, 9 —The dnric lines ludicnte tlinse i>npil8 who -wma bom ilciif, nud tho light lines tliose who became deaf rrom disease or accident \ 

T H E FORMATION O F A D E A F V A R I E T Y O F T H E HUMAN RACE. 37 There are indications also of a similar though less disturbance m the numbers of tliose who lost their heanng from disease daring the decade 1811 to 1820. A n examination of the reports of the American Asylum and Illinois institution may throw light upon the nature of these'disturb- ances. By classifying the pupils of these institutions according to their period of birth, we obtain the results that are exhibited graphically in the foregoing diagram (Fig. 9). The apparent decrease in the number of pupils born in the last two decades is susceptible of simple explanation. Very few pupils are received into institutions for the deaf and dumb before they are ten or twelve years of age, while it is not uncommon for pupils to be admitted at twenty or twenty-five years of age or even older. A pupil born lu the year 1869 would only be 13 years of age in 1882 (the date of the Illinois report). I t la evident, therefore, that of those deaf mutes who were born in the decade 1860 to 1869 who will ultimately make their appearance in the Illinois institution all had not been received at the date of the report. A similar explanation can be given in the case of the American Asylum. The dotted lines indicate those portions of the curves which are known to be inaccurate on this account. In regard to the American Asylum the abnormal increase in the number of pupils who became deaf from disease or accident who were born during the decade 1810-'19 is very marked. Another abnormal increase is observable m the number of those who became deaf in the decade 1860-'69. Indeed, the relations of the congenital and non congenital deaf-mutes are reversed in a similar manner to that shown in F i g . 8. I n regard to the Illinois pupils (see Fig. 9) it will be observed that the increase in the numbers of the non-congenitally deaf is so enormous, that of the pupils who were born in the decade 1860-'69 there were more than three times as many non-congenitally deaf as there were congenitally deaf, and of those born in 1870-'79 more than four times, whereas the census returns show that more than half of all the deaf-mutes living in this country (1880) were born deaf. ^ In the reports of the American Asylum and Illinois institutions the year when each pupil was admitted and his age when admitted are noted, with few exceptions. From these elements the period of birth has been calculated. The period when hearing was lost has also been -ascertained in all cases where the age of the pupil when deafness occurred is stated in the report I n tables K and L of the Appendix the non-congenital pupils of both institutions are class- ified according to the period when hearing was lost and according to the disease that caused deafness. I n regard to the Illinois report it is unfortunately the case that the age of the pupil when deafness occuired is not stated in 327 cases out of 947, so that we are only able to classify about two-thirds of the cases in this way. The results are shown graphically m the upper dia- grams of F i g . 10. From the tables m the Appendix we have clear evidences of two epidemics of " spotted fever,"* or epidemic cerebro spinal meningitis. One epidemic during the decade 1810 to 1819, reaching a maximum in the year 1815, and the other (a great epidemic) in the decade 1860 to 1809, continuing m the last decade, 1870 to 1879. The pupils who became deaf from cerebro spinal meningitis and from scarlet fever are clas- sified according to the period when deafness occurred in the lower diagrams of Fig. 10. The numbers of the non-congemtally deaf are evidently subject to great and sudden fluctuations on account of epidemical diseases which cause'deafness, whereas the growth of the congenitally-deaf popula- tion seems to be much more regular. •According to Dr Russell Reynolds "spottod^fever" is a'popiilar name for epidemic cerebro-spinal meningitis See "A System of Medicine," 1880, Vol I, pp 296-7 

38 MEMOIRS O F T H E NATIONAL A C A D E J I Y O F SCIENCES. so 30 to eo Anu tcan van. ou J taut vUon 40 to 30 too 1 300 « 1 SO / -« f l \ 80 /9 t \ to 1 eo 1 ^ r \ w 1 « ff 1 — 1 to t 1 1 30 1 too 1 m so 1 \ 1 so eo 1 30 \ M t 1 30 20 1 s \ 1 I 1 1 1 I 1 1 I § \ i 1 Period *\ 1 1 1 1 1 1 1 i 1 1 i*( 1 1 1 i 1 % i 1 1 1 1 1 1 i 1 i i * 1 N S s 1 1 1 »( *> SI a a 1 30 30 An lauH A/sn and 30 go i 'ereiu •arUt a taiie ' Tea,w \— 80 1 1 10 • 1 10 • 1 ; 1 WO / 1 MO so i' 1 I 1 SO so ; ! 1 1 to \ 70 \ TO \ 00 eo 30 1 30 \ •lO \ 40 1 30 1 • 30 1 so • / 30 / t 10 1 to / 1 1 1 1 s 1 1 \ \ 11 1 1 •i SI •« I as « S 1 1 1 1 IN 1 1 1 1 1 1 1 1 1 1 1 1 1 s 1 1 1 i i i i § •1 1 « IS •£ N % • s IS <e 1 1 s • \\\ 1 1 1 •I |FI0 10 ca 1 1 1 1 5 § s »t 

T H E F O R M A T I O N O F A D E A F V A R I E T Y O F T H E HUMAIT R A C E . 39 I n Table T of the Appendix I have classified 215 cases of deaf-mutes who are the oft spring of deaf mutes according to their period of birth, separating those who have one parent deaf from those who have both. The results are shown graphically in F i g . 11. 76 76 72 Dea off' of ' et^-i tult •part its 7S 68 68 /\ // / St 64 SO 60 \ S6 \ SS S3 / S2 — \ // 4S as 44 \ 44 40 \\ 40 r 36 / \ \ \ \ — V — -\— \ 36 3S / \ V V 3S 2S 28 24- ^\ \» \ 24 \ \ 20 \ 20 N 1€ 16 — V - 12 12 a 3 4 1 1 1 1 I f f 1821—1830 1781-1790 1 1 -s 1 1 M v> N V> t? i ^ > 1 1 1 1 1 ^1 1 1 1 1 >5 <5> 5? SI 11V ^ 1 P I G 11 —The dark line indicates the denf mates who have both parents deaf Tbe lower light line represents those who have one parent deaf, and tho upper line the total number of deaf mutes returned who have one or both parents deaf No deaf-mute having both parents deaf has been returned who was born before the year 1832. I t seems probable, therefore, that the oldest deaf-mute in the country whose parents were both deaf-mutes is only now a little past middle age. We have therefore received into our institutions only <7ie_^rs* </eneration of deaf-mutes born from the intermarriage of deaf mutes. The apparent decrease in the number born since 1861 does not necessarily indicate a real decrease, for many of the deaf-mutes born m the decade 1861 to 1870 have not yet been admitted to institutions for the deaf and dumb. Those portions of the curves that we know to be unreliable from this cause are represented in dotted lines. I n concluding this portion of my subject it may be well to institute a comparison between the deaf-mute population and the total population of the country as returned by the census of 1880. 

40 MEMOIRS OP T H E NATIONAL A C A D E M Y O F SCIENCES. I n Table U of the Appendix I have classified the people of the United States according to the decades in which they were born, and have reduced the number born in each decade to a percent- age of the whole In the same table I have classified the 12,154 congenital deaf mutes mentioned by Mr. Wines m a similar manner, and also the deaf mutes who have both parents deaf-mutes. We can .thus examine upon the same scale the distribution of the three classes according to age. The results are shown graphically in the diagram, F i g . 12. The ordinates represent the percentage of the whole who were born in the decades indicated by the abscissfe I f we assume that the numerical relation now existing between congenital deaf-mutes and hearing persons of the same age approximately repiesents the proportion of the congenitally deaf to the whole population born at the period when they were born, we have a means of comparing the growth of the congenitally deaf population with that of the population at large. The indications are that the congenital deaf-mutes of the country are increasing at a greater rate than the population at large; and the deaf-mute children of deaf-mutes at a greater rate than the con genital deaf-mute population. 

FiO.12. LEOENI).—^Distribation according to age (1) of the whole population of the United States, (2) o£ the congenital deaf mute population, and (3) of deaf mutes who are the children of deaf mates The ordinates of the corves represent the percentage of the whole who were born in the decades indicated by the abscisste represents population of the United States represents congenital deaf mutes of the United States represents deaf mutes who are the children of deaf mutes represents portion of the curves known to be unreliable on account of incomplete returns 1771-1780 781-1770 1771-1800 181-1820 1821-1830 I83l-I8h0 I8m-I850 1851-1860 1861-1870 1871 - 1 8 8 0 S. MIS. 110. 1 4«