and the Intensity of Human Life. 199 



from observations made in a particular country or even ]iniite<l 

 dibtrict, and confined to an abridged period of time, might be 

 applicable to all species of concerns depending on the pro- 

 bable duration of specific lives. To admit, as universal, any 

 law of mortality whatsoever, under the present constitution of 

 society, would be an error no less palpable. On the other 

 hand, a very extraordinary notion, that the law of mortality 

 had undergone a material alteration within a century, seems 

 to have gained credit with many, who fail to reflect on the 

 immutable character of all the laws of nature without excep- 

 tion. Let us endeavour to place these matters in their true 

 point of view. 



Our object is to establish, that no law of mortality can be 

 considered absolute, nor otherwise than as a particular modi- 

 fication of some primary law of nature, in all probability un- 

 discoverable ; — that any stated hiw of mortality must be exclu- 

 sively referable to a specific sex, and to a class of people pre- 

 cisely defined, according to certain general conditions under 

 which all comprised in that class are understood to exist; — that 

 a well-constructed law should, amongst other characteristics, 

 exhibit in regular gradation the mathematical expressions of 

 the intensity of life, for each year of age, so as to harmonize 

 with physiological observations in that resi:)ect ; — and lastly, 

 inasmuch as such intensity materially differs in the two sexes, 

 as also variously at different years of age, — that the progressive 

 increase or decrease of such comparative life-intensity, relative 

 to similar ages, ought to be distinctly expressed in the law re- 

 ferable to the one and in the law referable to the other sex, 

 both belonging to the same class of selection. It is only when 

 the law is constructed on those strict principles, that it can be 

 truly applicable, without danger of gross miscalculation. 



Doubtless, the human species, in this respect like all other 

 species of animals, when existing under the conditions best ap- 

 propriated to, and most congenial with, their respective na- 

 tures, are each of them subject to a primary law by which the 

 waste of life amongst them is governed ; an(l it is as little to be 

 doubted that this primary law, if it coukl be ascended to, would 

 exhibit the most favourable specimen possible of human life. 

 Even under those conditions, such a law would still be liable 

 to many modifications, depending on accident and other cir- 

 cumstances ; the same with the brute creation, in its immense 

 varieties, and amongst which those which are domesticated, or 

 others most exposed to hostile enterprise, become subject to 

 rates of nmrtality far different from their original determina- 

 tion. Hut a nmltitudc of lurther modifications of the primary 

 luw, relative to mankiuil, have been introduced conscfiuently 



to 



