55G PROCEEDI^^GS OF SECTIOX Gl. 



elsewhere than in West Australia, and whose time of residence 

 within that State was ascertained, recorded, and tabulated. Another 

 12'6 per cent, were born in West Australia, so that it can be 

 claimed that Figure 6 is sufficiently representative of the introduced 

 phthisis to enable deductions to be drawn from it. 



Figure 6 sets out for each year under consideration the deaths 

 from phthisis of people not born in Western Australia according to 

 the number of years' residence in that State. The curves show a 

 definite sequence. 



In 1903 the maximum point is during the ninth year of residence 

 — that is, the greatest number of deaths took place among these 

 people who entered the State during the year 1895-6. 



In 1904, 1905, and 1906 similarly the greatest number of deaths 

 took place among those who entered the State in the years 1895-1896. 

 In 1907 the maximum was among those who entered the State in the 

 year 1896-7. 



Reference to Figure 2. — The curve of the mean total population in 

 each year shows that during the years 1894-1897 a sudden rise in 

 population occurred, and then, after steadying a little for 3 years, 

 another rapid rise began. From 1894-7 the sudden increase was due 

 to the rush of people attracted by the discovery of goldlields. The 

 later rise has been due partly to the discovery of fresh goldfields, and 

 partly to an energetic policy of importing agricultural settlers pursued 

 by the authorities. The effect of such an increase of population can 

 be seen in many Avays. Its effect on the incidence of diphtheria has. 

 already been pointed out by the writer in a previous paper ("' Public 

 Health," July, 1908). 



Figure 3 shows that the curve was at its lowest, 1895-8, and 

 similarly Figure 1 for West Australia shows a marked depres- 

 sion in the curve between 1893-1900. Both these are due to the 

 sudden large increase in population. It can be asserted without hesi- 

 tation that much of the increase in population in Western Australia 

 was obtained at the expense of the other Australian States, and in 

 vicAv of Figure 6 the deduction that some at least of the people 

 that died from phthisis in West Australia during 1903-7 came 

 from the other States in Australia is reasonable. In this connection 

 the remark of Dr. Bulstrode, after a full consideration of the experi- 

 ence of the various authors, may be quoted : — " Obviously a consider- 

 able number of persons with phthisis lived and worked for many years 

 after the recognition of their ailment, and this, independently of 

 treatment in sanatoria {loc. cit. p. 115). But, irrespectively of 

 whether the people under discussion were affected with either recog- 

 nised or unrecognised pulmonaiy tuberculosis on their arrival in this 

 State, it may be assuiaed that had the unusually large migration not 

 taken place between 1894-1897, some at least of these cases might 

 have died from phthisis in the States from which they oi'iginally 

 came, and so the incidence of phthisis would have been more evenly 

 distributed, and the decline in phthisis death-rate have included 

 West Australia, and so have been uniform throughout all of the 

 Australian States. 



A consideration of why it is that the phthisis death-rate is show- 

 ing a marked tendency to decline affords a fascinating problem, the 



