Page:EB1911 - Volume 07.djvu/904

 (1) the explanation of a remarkable line of white foam that extends along the axis of the lake almost every morning—supposed by Blanckenhorn to mark the line of a fissure, thermal and asphaltic, under the bed of the lake, but otherwise explained as a consequence of the current of the Jordan, which is not completely expended till it reaches the Lisān, or as a result of the mingling of the salt water with the brackish spring water especially along the western shore; (2) a northward current that has been observed along the east coast; (3) various disturbances of level, due possibly to differences of barometric pressure; (4) some apparently electrical phenomena that have been observed in the valley. Before we can be said to know all that we might regarding this most interesting of lakes further extensive scientific observations are necessary; but these are extremely difficult owing to the impossibility of maintaining self-registering instruments in a region practically closed to Europeans for nearly half the year by the stifling heat, and inhabited only by Bedouins, who are the worst kind of ignorant, thievish and mischievous savages.

 DEADWOOD, a city and the county-seat of Lawrence county, South Dakota, U.S.A., about 180 m. W. of Pierre. Pop. (1890) 2366; (1900) 3498, of whom 707 were foreign-born; (1905) 4364; (1910) 3653. It is served by the Chicago, Burlington & Quincy and the Chicago & North-Western railways. It lies on hilly ground in the canyon of Whitewood Creek at an elevation of about 4530 ft. Deadwood is the commercial centre of the Black Hills. About it are several gold mines (including the well-known Homestake mine), characterized by the low grade of their ores (which range from $2 to $8 per ton), by their vast quantity, and by the ease of mining and of extracting the metal. The ore contains free gold, which is extracted by the simple process of stamping and amalgamation, and refractory values, extracted by the cyaniding process. Several hundred tons of ore are treated thus in Deadwood and its environs daily, and its stamp mills are exceeded in size only by those of the Treadwell mine in S.E. Alaska, and by those on the Rand in South Africa. The discovery of gold here was made known in June 1875, and in February 1877 the United States government, after having purchased the land from the Sioux Indians, opened the place for legal settlement.

 DEAF AND DUMB. The term “deaf” is frequently applied to those who are deficient in hearing power in any degree, however slight, as well as to people who are unable to detect the loudest sounds by means of the auditory organs. It is impossible to draw a hard and fast line between the deaf and the hearing at any particular point. For the purposes of this article, however, that denotation which is generally accepted by educators of the deaf may be given to the term. This makes it refer to those who are so far handicapped as to be incapable of instruction by the ordinary means of the ear in a class of those possessing normal hearing. Paradoxical though it may seem, it is yet true to say that “dumbness” in our sense of the word does not, strictly speaking, exist, though the term “dumb” may, for all practical purposes, fairly be applied to many of the deaf even after they are supposed to have learnt how to speak. Oral teachers now confess that it is not worth while to try to teach more than a large percentage of the deaf to speak at all. We are not concerned with aphasia, stammering or such inability to articulate as may be due to malformation of the vocal organs. In the case of the deaf and dumb, as these words are generally understood, dumbness is merely the result of ignorance in the use of the voice, this ignorance being due to the deafness. The vocal organs are perfect. The deaf man can laugh, shout, and in fact utter any and every sound that the normal person can. But he does not speak English (if that happens to be his nationality) for the same reason that a French child does not, which is that he has never heard it. There is in fact no more a priori reason why an English baby, born in England, should talk English than that it should talk any other language. English may be correctly described as its “mother tongue,” but not its natural language; the only reason why one person speaks English and another Russian is that each imitated that particular language which he heard in infancy. This imitation depends upon the ability to hear. Hence if one has never heard, or has lost hearing in early childhood, he has never been able to imitate that language which his parents and others used, and the condition of so-called dumbness is added to his deafness. From this it follows that if the sense of hearing be not lost till the child has learnt to speak fluently, the ability to speak is unaffected by the calamity of deafness, except that after many years the voice is likely to become high-pitched, or too guttural, or peculiar in some other respect, owing to the absence of the control usually exercised by the ear. It also follows that, to a certain extent, the art of speech can be taught the deaf person even though he were born deaf. Theoretically, he is capable of talking just as well as his hearing brother, for the organs of speech are as perfect in one as in the other, except that they suffer from lack of exercise in the case of the deaf man. Practically, he can never speak perfectly, for even if he were made to attempt articulation as soon as he is discovered to be deaf, the fact that the ear, the natural guide of the voice, is useless, lays upon him a handicap which can never be wiped out. He can never hear the tone of his teacher’s voice nor of his own; he can only see small and, in many instances, scarcely discernible movements of the lips, tongue, nose, cheeks and throat in those who are endeavouring to teach him to speak, and he can never hope to succeed in speech through the instrumentality of such unsatisfactory appeals to his eye as perfectly as the hearing child can with the ideal adaptation of the voice to the ear. Sound appeals to the ear, not the eye, and those who have to rely upon the latter to imitate speech must suffer by comparison.

Deafness then, in our sense, means the incapacity to be instructed by means of the ear in the normal way, and dumbness means only that ignorance of how to speak one’s mother tongue which is the effect of the deafness.

Of such deaf people many can hear sound to some extent. Dr Kerr Love quotes several authorities (Deaf Mutism, pp. 58 ff.) to show that 50 or 60% are absolutely deaf, while 25% can detect loud sounds such as shouting close to the ear, and the rest can distinguish vowels or even words. He himself thinks that not more than 15 or 20% are totally deaf—sometimes only 7 or 8%; that ability to hear speech exists in about one in four, while ten or fifteen in each hundred are only semi-deaf. He rightly warns against the use of tuning forks or other instruments held on the bones of the head as tests of hearing, because the vibration which is felt, not heard, may very often be mistaken for sound.

Dr Edward M. Gallaudet, president of the Columbia Institution for the Deaf in Washington, D.C., suggests the following terms for use in dividing the whole class of the deaf into its main sections, though it is obviously impossible to split them up into perfectly defined subdivisions, where, as a matter of fact, you have each degree of deafness and dumbness shading into the next:—the speaking deaf, the semi-speaking deaf, the mute deaf (or deaf-mute), the speaking semi-deaf, the mute semi-deaf, the hearing mute and the hearing semi-mute. He points out that the last two classes are usually persons of feeble mental power. We should exclude these altogether from the list, since their hearing is, presumably, perfect, and should add the semi-speaking semi-deaf before the mute semi-deaf. This would give two main divisions—those who cannot hear at all, and those who have partial hearing—with three subsections in each main division—those who speak, those who have partial speech and those who do not speak at all. Where the hearing is perfect it is paradoxical to class a person with the deaf, and the dumbness in such a case is due (where there is no malformation of the vocal organs) to inability of the mind to pay attention to, and imitate, what the ear really hears. In such cases this mental weakness is generally shown in other ways besides that of not hearing sounds. Probably no sign will be given of recognizing persons or objects around; there will be