president's address. SECTIOX Gl. 515 



■these the overlap is considerable, for in considering human life as 

 affected by age or by disease, the vital element is a necessaiy 

 measure of the economic. Hence, the statistical matter will fall under 

 one or the other category, according to the dominant purpose of the 

 inquiry, and this must be understood in all that follows. 



Vital Statistics (A). 



2. Poioulation and its VariaHon. — The increase of population and 

 its variations are ordinarily the crude results, and as already indi- 

 cated are not immediately comparable. In young countries where 

 the flux of population, owing to migration differences, is essentially 

 different from that of old populations, the distribution according to 

 sex and age differs materially from those of older countries. It 

 folloAvs from this that apart from racial, climatological, economic, and 

 traditional differences, the following rates are immediately influenced, 

 viz. : — 



(i.) Total birth rate and ratio of illegitimate to legitimate 

 births, 

 (ii.) Total fertility rates or rates of birtlis to total number of 



vromen of each age within the child-be arine npiind. 

 (iii.) Total death rate and sex-ratio of deaths, 

 (iv.) Infantile mortality rate, 

 (v.) Eft'ect of infantile mortality on birth rate, 

 (vi.) Death rates of each sex for particular diseases, 

 (vii.) Marriage rates, and distribution according to age. 

 (viii.) Disease and its duration, having regard to sex, and age 



of incidence. 

 With a single exception,* the discussion of the reduction of these 

 to Avhat may be called their nonnal form has not yet been made for 

 Australian data, nor, indeed, for the data of the world generally; 

 hence, at the present time, Ave have to be content mainh' with com- 

 parisons of crude results. 



Suppose, however, that results for birth, death, or marriage 

 rates were so corrected as to conform to identity of age distribution^ 

 they would not even then be necessarily comparable for all purposes. 

 The average peinod of life and the cli mat erics vary in different 

 climates, and perhaps also from age to age; hence, identity or 

 similai'ity in the characteristic features of human life may be properly 

 seen only thi'ough comparisons of " correspmiding states,^'' analogous 

 for example, to the states defined by that term in the physical theoiy 

 of the behaviour of gases. 



To attain to a deeper understanding of the significance of our 

 statistical residts requires solutions of the type suggested, but they 

 have not yet been made. 



3. Oscillatory Character of Population Phenomena. — For many 

 purposes one may substitute for actual phenomena certain concepts of 

 them. For example, the annual increase of population may be sup- 

 posed to conform to the idea of regular and continuous growth of 

 population. Actually, however, increase by birth and diminution by 

 death is essentially oscillatoiy or periodic. It is so in virtue of the 



* See "On the Influence of Infantile Monilitv on Birthrate."' Journ. Roy. Soc. 

 K". S. Wale.s, 1908-1). l)y G. H. Knibl.s. 



