4 THE HEALTH OF HORAl^T. 



miinipulating fiojures relating to currency, crops, tariffs, or 

 causes of death." Even then, in comparisons between different 

 countries, he must he in possession of a ^ood up-to-date 

 library of statistical reference, and be able by experience to 

 determine readily good from bad authority, and have a wide 

 knowledge of the best sources of information. The knowledge 

 and exact sijrnification of the current statistical terms are all 

 essential ; for not a little confusion and conflicting opinion 

 arise from misinterpretation of the true significance of terms 

 in common use among statisticians. As the demonstration and 

 acceptation of the truth of the statements made by me re- 

 garding the present healthy condition of Hobart largely 

 depend upon clearly understanding the difference between a 

 " Total Death Rate" and a " Health Standard Rate " ; in dis- 

 cerning and separating preventible causes of death from the 

 non-preventible ; and in marking the difference, proportion, 

 and effect which in age and sex determine a General Death 

 Rate — quite apart from any consideration of health, — it is 

 necessary at the outset that such preliminary remarks as 

 have been made should be carefully weighed, and that a few 

 simple illustrations should be given to enable the uninitiated 

 to comprehend the difficulties of statistical comparison between 

 different periods and different places, without which a true 

 estimate cannot be formed of the comparative healthiness of 

 diflferent cities. No two cities, or two periods in the same 

 place exactly, agree in the age or sex combination of their 

 respective populations ; but, such is the remarkable influence ot 

 these factors in the actual determination of a general death- 

 rate that, unless such differences are strictly determined and 

 allowed for, it is as likely as not that the healthiest period or 

 the healthier place would be placed erroneously in the worst 

 position, while the least healthy period or the least healthy city 

 might appear erroneously in the best. 



The following illustration of the disturbing effect of great 

 disproportion of nutnbers at different ages is taken from the 

 two divisions of the Registration District of Hobart for the 

 year 1894 :— 



