200 Mr. Corbaux on the Lwws of Mortality, 



to civilization, with its attendant inequality in the distribution 

 of social advantages and disadvantages, and to the different 

 circumstances of climate, soil, government, mode of living, 

 moral and temperate habits or the contrary ; as also to the 

 greater or less liability to disease and to other causes endan- 

 gering life, or tending to abridge it. Hence it becomes an in- 

 dispensable requisite, that any stated law of mortality should 

 be referable to some definite class of individuals, existing un- 

 der circumstances nearly common to them all. And when it 

 is considered that the laws hitherto published, as founded upon 

 particular sets of local observations, made at certain limited 

 periods, differ widely from each other in all their results and 

 deductions, — it must follow that the indiscriminate applica- 

 tion of any specific law, to other classes of lives than the one 

 to which it is exclusively referable, cannot fail to generate mis- 

 calculations of the utmost consequence regarding the value of 

 contingent property, contradistinguished from that which beai's 

 the character of certainty. 



It is not merely that two classes of persons, without distinc- 

 tion of sex, may exist under circumstances materially different 

 as affecting the rates of their mortality ; differences of the same 

 tendency may be no less considerable between the two sexes, 

 though they existed under circumstances as nearly alike as 

 could possibly be supposed. It has therefore been another 

 error, to have admitted the application of any law of mortality 

 to both sexes indiscriminately. 



The whole course of a life, male or female, is divisible into 

 successive periods, more or less protracted ; and during each 

 of which, the conditions of existence are maintained, with very 

 little variation, for either sex singly considered. But those 

 conditions necessarily undergo, in some important respects, a 

 notable alteration, modifying not only the rates of mortality 

 from one pei*iod to another, but also the progressive decrease 

 of the intensity of life ; nor do those periods, or natural divi- 

 sions of any life, coincide as to both sexes. This considera- 

 tion, more particularly belonging to the department of physio- 

 logy, ought always to be kept in view when any law of mortality 

 is constructing ; but the custom has hitherto been completely 

 to discard it. Notwithstanding the palpable absurdity of sup- 

 posing, either that the waste of life, from birth to old age, was 

 governed by any uniform law; or that males and females, whose 

 physical constitutions and whose vocations are widely dif- 

 ferent, were subject to exactly the same rates of mortality du- 

 ring similar periods of their respective ages; admissions such 

 as these have been practically proceeded upon, and pertina- 

 ciously adhered to. It would only be fastidious to enter here 



into 



