SCIENCE 



NEW YORK, MARCH 31, 1893. 



ON THE ETHNOLOGICAL CHARACTERISTICS OF THE 

 HUMAN NASAL CANALS, CONSIDERED AS AN ECO- 

 NOMIC ADAPTATION. 



BY WILLIAM C. BRAJSLIN, M.D , BROOKLTK, N,Y. 



The human voice bears a constant relation to the physical coo- 

 struction of the voice-producing organs. 



Deep, manly tones are the constant sequelae to a larynx of large 

 proportions, to long and slowly vibrating vocal cords; while the 

 childish treble and the high-pitched voice of the female are the 

 natural productions of the smaller larynx with its shorter, and, 

 CDnsequently, more rapidly vibrating, vocal cords. 



Of equal importance in the modulation, tone, and indefinable 

 individual peculiarity of the voice, is the construction of the nose 

 and pharynx. The anatomical construction of these organs is as 

 varying as is that of the facial features, and, to the trained eye, 

 the individual peculiarities are as apparent. 



It is not to be wondered at, therefore, that the racial peculiari- 

 ties, in regard to the anatomical structures, of the internal nares- 

 are particularly striking. 



The external anatomical construction of the nasal organ char- 

 acteristic of the native African, is as distinguishing an ethnologi- 

 cal differentiation as are the color of his skin, the texture of his 

 hait, and the development of his brain. 



Corresponding distinctions characterize the internal structure^ 

 of this portion of the upper air tract of this race. Immediately 

 on passing the anterior openings of the nares, the human nasaf 

 canals spread out into deeper and wider channels. These cavities, 

 separated by the septum narium, are corrugated on their opposite- 

 surfaces by the three pairs of turbinated bodies, whose "curled- 

 leaf" surfaces increase enormously the extent of surface area of 

 the nasal mucous membrane. 



The bones of the cranium taking part in the formation of the 

 nasal cavities, so differ in the African race as to make these 

 canals wider, shorter, and less deep than those of other races. 

 The bony ridges coursing their long axes, known as the turbinated 

 bones, are also more blunt and less prominent and have less of 

 the "curled-leaf" character. 



Measurements of a single specimen of an average skull of either 

 race will suffice to show this difference in bony framework. 



width of au'erior nasal canals 



Height of anterior nasal canals 



Length of nasal canals (from anterior nasal spine to pos- 

 terior nasal spine) 



Length of nasal canals (from anterior nasal spine to pos- 

 terior-superior angle of vomer) 



Length of skull 



Breadth of skull 



The continuance of these peculiarities in the lineal descendants 

 of the negro race as seen in America to-day, is markedly striking 

 to the student of the comparative anatomy of this region. 



One, indeed, cannot fail to note in any of the clinics devoted to 

 the diseases of this region the increased advantage which accrues 



to the possessor of the vvi.ier nasal canals when pathological con- 

 ditions, resulting in thickening of the lining mucous membrane, 

 attack this portion of the anatomy, 



Ooe of the most prominent American larynxologists was ena- 

 bled, by means of the more patent condition of the nasal canals- 

 in his negro patients,' — tbe American descendants of this race, — 

 to make a contribution of certain facts to medical science, not 

 otherwise easily obtainable. 



Mr. Wallace^ supposes that the origin of the African race was 

 due to a migration of some part of the race of ancestral man 

 from the great Euro-Asiatic plateau, and that his present char- 

 acteristics are the result of physiological modifications due to 

 climatic influence. 



If we accept this likely explanation in regard to the special 

 anatomical construction of the nasal cavities of the negro and his 

 descendants, our logical conclusion is that they must present 

 characteristics specially adapted for preparing the inspired air of 

 a tropical climate for reception into the lung structures. We 

 must suppose that ages of contact of his nasal mucous membrane 

 with the atmosphere of a tropical climate have brought about, by 

 the laws of natural selection, a nasal construction the most nearly 

 adapted to dealing with the problem of the irritating qualities of 

 a tropical atmosphere, of any existing race. 



It does not seem probable that the evolution of the construction 

 of the nasal canals, characteristic of the African type, has been 

 due to any reason of better serving the purposes of the gustatory 

 sense. The custom of regarding the nose as the organ of smell" 

 has. very properly, become modified to that of regarding it as ■ 

 primarily an organ of respiration. It is the proper channel for- 

 the conduction of air to the lungs for purposes of oxidation. 



As has been stated, the means of warming, of moistening, and 

 o-f freeing the air from dust and other irritating qualities are here 

 most admirably afforded. The sense of smell must, indeed, also 

 be regarded as a protective provision for the avoidance of sub- 

 stances irritating to the more delicate lung substance. 



Had its purposes demanded an assistance to the procuring of 

 fo )d or to the avoidance of poisonous food, a development of the 

 gustatory sense, such as is found in the dog or other animals, 

 would have been found in the human species. This, however, is 

 not the case. The acute sense of smell is not one highly developed' 

 or inherent in man. Indeed, this sense is soon entirely lost in 

 conditions of the nasal canals which interfere with its respiratory 

 function. 



The difference we have noted in the anatomical construction! 

 of this portion of the upper air tract — the nasal canals — is natu- 

 rally resultant in different pathological effects in the different 

 races as regards the particular portions of the respiratory tract 

 most frequently becoming the seat of disease processes under the 

 influence of atmospheric irritation. Less protection is afforded 

 the lung structures of the negro race on account of the anatomi- 

 cal structure of his nasal canals, since less opposition to the 

 irritating factors of the atmosphere is jsresented, by reason of the 

 more patent and more direct course which the inspired air en- 

 counters. That the lung structure of this race in the United 

 States suffers from the irritation caused by degenerating atmos- 

 pheric conditions seems to the writer to be evinced by data of the 

 Tenth Report of Vital Statistics of the United States, compiled by 

 Dr. John S, Billings. 



Among many other facts of great significance in this compila- 

 tion we are shown that the number of deaths per 1,000 from con- 

 sumption — the disease ?)ios< dependent, perhaps, upon irritating 

 qualities of the atmosphere — is not only greater among tbe col- 

 ored portion of our population, but it is in direct proportion 

 ' American Journal of the Medical Sciences, 1S83. 

 2 " Darwinism," p. 460. MacmiUan. 



