278 



THE POPULAR SCIENCE MONTHLY. 



and the Sierra Nevada on the west. The 

 present volume does not include all the re- 

 sults of Professor Cope's researches, for 

 another is to follow. Professor Hayden 

 well says of the whole, in his letter trans- 

 mitting the report, that " the amount of 

 new matter toward the origin and history 

 of the mammalian groups brought together 

 by the author in these two volumes is most 

 extraordinary, and will probably never be 

 surpassed." In this single volume are given 

 the vertebrata of the Eocene and of the Low- 

 er Miocene, less the Ungulata, with descrip- 

 tions of 349 species, which are referred to 

 1 25 genera. The author sums up fifteen im- 

 portant results that have accrued through the 

 researches here set forth in the discovery of 

 new genera and families, among which are 

 the discovery of the phylogenetic series of 

 the Canida;, or dogs, and the same of the 

 ancestors of the Fclidce, or cats. As the 

 book was stereotyped in 1883, all conclu- 

 sions of later date than that are necessarily 

 excluded from it ; but the author's final 

 conclusions from the material described 

 are mostly to be found in a series of illus- 

 trated articles he has been publishing in 

 the " American Naturalist " in the years 

 1883-'85. 



The Ten Laws of Health ; or, IIow Dis- 

 eases ARE PRODUCED AND PREVENTED. By 



J. R. Black, M. D. Published by the 

 Author. Baltimore. Price (by subscrip- 

 tion), $2.50. 



A part of this book was published sev- 

 eral years ago. The edition having been 

 exhausted for many years, the matter has 

 been revised to bring it up even with the 

 progress of the age, and an entirely new 

 part has been added, comprising nearly a 

 fourth of the present volume, on thorough 

 disinfection within the sick-room and the 

 sick-bed as the most effective means for pre- 

 venting the spread of contagious diseases 

 and epidemics. The author is a strong be- 

 liever in the doctrine that disease is unneces- 

 sary and preventable ; in his view man is the 

 most sickly of beings, because those which 

 means most men " who neither know nor 

 strive to be governed by law in the uses 

 they make of themselves, become victims to 

 hundreds of evils in the various forms of 

 disease." The ten laws of health are taken 

 up in their order and explained ; the viola- 



tions of them are shown, with their attend- 

 ant results ; and the mode of observing them 

 is taught. The first law is, that a pure air 

 must be breathed. To obtain this within 

 the house, supposing that the surroundings 

 arc pure, " the great and imperative require- 

 ment is air-movement, a decided though gen- 

 tle current through an occupied room day 

 and night." Second ; the food and drink 

 must be adequate and wholesome. The evil 

 to be guarded against in the United States 

 is excess, for inadequateness or a deficiency 

 of food on this continent, although the com- 

 mon sentiment is quite the reverse, is not 

 often a direct cause of disease. As to the 

 quality of our food, as we prepare it, " of 

 the many books published on the subject of 

 cooking, there are few, if any, that have not 

 receipts by the score which can not be ex- 

 celled for producing indigestion." The ef- 

 fects of tea and coffee and alcoholic stimu- 

 lants are carefully considered. The third 

 law enforces the necessity and judicious 

 practice of out door exercise ; and the fourth 

 law prescribes adequate and unconstraining 

 covering for the body. The fifth law con- 

 cerns the exercise of the sexual function. 

 Under the head of the sixth law are consid- 

 ered the effects of changes of climate, and 

 the measures to be taken for safe acclimati- 

 zation when that step is taken. Regarding 

 changes of climate for the sake of health, 

 the author concludes, from a survey of the 

 available facts on the subject, " that an im- 

 prudent change of climate more frequently 

 destroys the health of the healthy than it 

 cures the sickness of the sickly." The sev- 

 enth law relates to the choice of occupation. 

 Its admonition is to select such pursuits as 

 do not cramp and overstrain any part of 

 the body, or subject it to irritating and poi- 

 sonous substances ; and, of course, to avoid 

 those of an opposite character. Next, we 

 are to keep personally clean, bathing sys- 

 tematically and changing regularly all cloth- 

 in" next to the skin. " Those who for month 

 after month, and even for year after year, 

 do not cleanse and invigorate the skin by 

 frequent baths, followed by brisk friction 

 of the skin, lose the good offices of a very 

 active organ of regeneration, and cause their 

 blood to be in a state very favorable for the 

 production of disease from slight causes." 

 Ninthly, we must preserve the mind in a trail- 



