SCIENTIFIC LITERATURE. 127 



but also contribute to the scattering of population over wider areas. 

 The most potent factors in attracting people to the cities were, in former 

 times, the commercial facilities they afforded, with opportunities to ob- 

 tain employment in trade, and are now the opportunities for employment 

 in trade and in manufacturing industries. The cities, however, do not 

 grow merely by accretions from the outside, but they also enjoy a new 

 element of natural growth within themselves in the greater certainty 

 of living and longer duration of life brought about by improved manage- 

 ment and ease of living in them, especially by improved sanitation, and 

 it is only in the nineteenth century that any considerable number of 

 cities have had a regular surplus of births over deaths. Migration city- 

 ward is not an economic phenomenon peculiar to the nineteenth cen- 

 tury, but is shown by the study of the social statistics and the bills of 

 mortality of the past to have been always a factor important enough 

 to be a subject of special remark. It is, however, a very lively one now, 

 and " in the immediate future we may expect to see a continuation of 

 the centralizing movement ; while many manufacturers are locating their 

 factories in the small cities and towns, there are other industries that 

 prosper most in the great cities. Commerce, moreover, emphatically 

 favors the great centers rather than the small or intermediate centers." 

 In examining the structure of city populations, a preponderance of the 

 female sex appears, and is explained by the accentuated liability of men 

 over women in cities to death from dangers of occupation, vice, crime, 

 and excesses of all kinds. There are also present in the urban popula- 

 tion a relatively larger number of persons in the active period of life, 

 whence an easier and more animated career, more energy and enterijrise, 

 more radicalism and less conservatism, and more vice, crime, and im- 

 pulsiveness generally may be expected. Of foreign immigrants, the least 

 desirable class are most prone to remain in the great cities; and with 

 the decline of railway building and the complete occupation of the public 

 lands the author expects that immigrants in the future will disperse 

 less readily than in the past, but in the never-tiring energy of Ameri- 

 can enterprise this may not prove to be the case. As to occupation, 

 the growth of cities is found to favor the development of a body of 

 artisans and factory workmen, as against the undertaker and employer, 

 and " that the class of day laborers is relatively small in the cities is 

 reason for rejoicing." It is found " emphatically true that the growth 

 of cities not only increases a nation's economic power and energy, but 

 quickens the national pulse. ... A progressive and dynamic civiliza- 

 tion implies the good and bad alike. The cities, as the foci of progress, 

 inevitably contain both." The development of suburban life, stimulated 

 by the railroad and the trolley, and the transference of manufacturing 

 industries to the suburbs, are regarded as factors of great promise for 

 the amelioration of the recognized evils of city life and for the solu- 

 tion of some of the difficulties it offers and the promotion of its best 

 results. 



Dr. James K. Crooh, author of The Mineral Waters of the United 

 States and their Therapeutic Uses* accepts it as proved by centuries 

 of experience that in certain disorders the intelligent use of mineral 



* Mineral Waters of the United States and tlieir Tlierapeutic Uses, with an Account of the Various 

 Mineral Spring Localities, their Advantages as Health Resorts, Means of Access, etc.; to which is 

 aided an Appendix on Potable Waters. By James' K. Crook. New York and Philadelphia: Lea 

 Brothers & Co. Pp. 588. Price, $3.50. - 



