7 oo THE POPULAR SCIENCE MONTHLY. 



But, putting aside this broad and philosophic view of the impor- 

 tance of mortuary statistics, it is evident that the application of their 

 deductions must be of great benefit to the physician as a practitioner 

 alone. This was perceived even as far back as the time of Sydenham, 

 who inculcated the doctrine that the treatment of all disease should 

 have a reference not only to the immediate symptoms and to the sea- 

 son, but also to the epidemic constitution of the year and the locality. 

 It lias been remarked by a distinguished author that "man is not 

 born, does not live, does not suffer, does not die, in the same manner 

 on all points of the earth. Birth, life, disease, and death, all change 

 with the climate and soil all are modified by race and nationality." 

 Medicine, with the other natural sciences, has now been obliged to 

 abandon vague hypotheses for truths determined by observation. 

 Numerical expressions are substituted for uncertain and conjectural 

 assertions. Only a limited number of facts are, however, contained 

 within the horizon of a few observers. The determination of the 

 laws of mortality requires a very wide range of observation, and a 

 considerable space of time, in order to eliminate accidental pertur- 

 bations. 



The next important element of vital statistics is that of birth. 

 Man is ushered into existence under natural circumstances almost as 

 impressive as those which circumscribe his duration of life, and which 

 attend its surrender. While tens of thousands are divesting their 

 being of earthly garb, and entering upon their eternal inheritance, still 

 greater numbers are assuming the heritage of life in forms moulded 

 by antecedent events, and stamped with ancestral peculiarities. If, 

 therefore, it be profoundly interesting to contemplate, arrange, and 

 study the multitude of agencies which impel this innumerable caravan 

 of pilgrims toward their destination, it is almost equally instructive 

 to analyze the manifold causes which have contributed to their as- 

 sembling together. Such particulars, when massed into statistics, be- 

 come of acknowledged importance to medical and social science. The 

 disparity in the sexes born at different periods, the average number 

 of women bearing twins, triplets, etc., the proportion of offspring 

 from native or foreign progenitors, the ages and occupations of par- 

 ents, the average number of children produced at different periods of 

 female life and in different seasons, the influence upon reproduction 

 of the relative ages of parents, the reciprocal relations between il- 

 legitimacy and modes of living these and other kindred questions 

 are of deep concern to the human race, and the source of their solution 

 lies in the largest accumulation of facts. 



Moreover, the actual number of births occurring in any community 

 each year is indispensable, in conjunction with other factors, for com- 

 puting the increment of population during years intervening between 

 those of official enumerations, and consequently for the determination 

 of the true death-rate. The remarkable precision with which this 



