10 



just before and just following tlie completion of the deep drainage^ 

 tlie doctor says that lie finds a sudden fall from an average during 

 the old system of 21-38 per 1,000 population to 14-34 in 1885 

 and 14*31 in 1886, the latter two being the years since tlie new 

 system was completed. The doctor questions the accuracy of 

 these figures, and gives reasons for the inference that the ofHcial 

 estimate of population for the last two years is incorrect. By a 

 metliod of calculation explained in his paj^er he arrives at the 

 conclusion that the population of Adelaide and suburbs was over- 

 estimated to the extent of about 26,700 in 1885 and of 43,100 in 

 1886, or in other words, that when compared with 1884 Adelaide 

 and suburbs lost in 1885 as many as 23,290 of its population, and 

 in 1886 a further number of 15,019, making in two years a loss- 

 of about 38,300 — i.e., nearly one-third of the estimated popula- 

 tion for 1884. I need but remind you that if a population be 

 over-estimated the rate of mortality per 1,000 will appear to be 

 less than it really is, and the locality will stand out as better 

 from a sanitary point of view than places where the estimate is 

 more correctly made. Having satisfied himself that Adelaide and 

 suburbs is over-estimated, and having worked out other figures 

 for himself. Dr. Jamieson calculates the rate of mortality on the 

 basis of his new figures, and he arrives at the conclusion that 

 according to his first mode of comparison the deep drainge has 

 produced some slight diminution in the rate of mortality. I leave 

 the question of population for the present because, although im- 

 jDortant, it need not be discussed in connection with the objection 

 I have to make against any conclusions either for or against deep 

 drainage being drawn from the doctor's calculations. The funda- 

 mental error into which Dr. Jamieson has fallen is the assumption 

 that the drainage area and the area of Adelaide and suburbs are 

 co-extensive. In 1885 and '86 the only places served by deep 

 drainage were Adelaide, Hindmarsh, and Thebarton, "Adelaide 

 and suburbs," as explained in the Registrar's report for 1886,. 

 means Adelaide and places within a radius of ten miles of it.. 

 This area includes Adelaide, Hindmarsh, and Thebarton, but it 

 also includes Port Adelaide, Norwood, Kensington, Unley, 

 Goodwood, St. Peters, Mitcham, Burnside, Glenelg, Semaphore, 

 Crafers, Prospect, and other smaller towns, none of which, except 

 a small part of St. Peters and Kent Town is connected with the 

 deep drainage. The population of Adelaide and suburbs in 1884 

 may be set down in round numbers at 123,500; that of the 

 drained part was about 52,300. It is therefore obvious that any 

 calculations on the effect of drainage based on the returns for 

 Adelaide and suburbs can only be inconclusive and misleading. I 

 fear that the Registration Office must take some part of the 

 blame for Dr. Jamieson's mistake. The published returns were 



