What action should be taken in respect to that part of the deaf who may marry under conditions favorable to the production of deaf offspring is not at present clear. Legislation would not appear on the whole to be advisable;[58] and the exertion of moral suasion, so far as possible, in the individual cases concerned would seem a more acceptable course. The matter, however, really belongs in the province of eugenics, and we will probably do best to await the authoritative pronouncement of its decrees before full procedure is resolved upon. CONGENITAL DEAFNESS AS AN INCREASING OR DECREASING PHENOMENON The final matter to be ascertained in respect to congenital deafness is whether it is relatively increasing or decreasing. The following table will show the number of the congenitally deaf in the censuses of 1880, 1890, and 1900, with their respective percentages and the ratios per million of population.[59] NUMBER OF THE CONGENITALLY DEAF IN 1880, 1890, AND 1900 RATIO PER TOTAL CONGENITALLY PER MILLION OF NUMBER DEAF CENT POPULATION 1880 33,878 12,155 35.6 242 1890 40,562 16,866 41.2 269 1900 37,426 12,609 33.7 166 From this it appears that congenital deafness is decreasing both in relation to all deafness, and to the general population. For further statistics, we may revert to our tables under adventitious deafness. In the tables relating to periods of successive recent years we find in respect to three schools, the New York and Western Pennsylvania institutions and the Maryland School, with certain fluctuations, no great change on the whole, though the last named school shows still a very high proportion. In two schools, the Michigan and Wisconsin, rather an increase is observed. In the Pennsylvania Institution, which covers a period of seventy years, there is a decrease from over 50 per cent to less than 40. A better test perhaps lies in the comparison of the proportions found for congenital deafness in the tables relating to periods widely separated in time. In these an increase is seen in the single case of the Ohio School; while a decrease is apparent in three, namely, the American and Iowa schools and the New York Institution. These decreases in percentages are respectively from 44.8 and 50.1 to 35.2; from 37.2 to 26.9; and from 42.9 to 38.0.[60] From the evidence that we have, then, taken together, it seems reasonable to conclude that congenital deafness is, though slowly, becoming less in the course of the years. CONCLUSIONS WITH RESPECT TO THE ELIMINATION OR PREVENTION OF DEAFNESS Most of what has been said in this chapter with respect to the elimination or prevention of deafness may be summed up as follows: