562 PROCEEDINGS OF SECTION G. 
CHEST aNpD LuNG CAPACITY. 
The chest grows slowly in its lateral dimension up to 
age 6 years, thence its increase to adult proportions is very 
regular, the only interruption being from 114 to 124 years, 
when the growth is almost suspended. The anterio-pos-. 
terior dimension or depth shows a slow growth till 74 
years, when it commences to increase with fair regularity 
up to 11 years. From 11 to 12 or 13 years its growth 
is slow, thence to 154 years the increase is more rapid, and 
still more rapid after age 15} has been passed. 
In boys the chest circumference at 54 years is 21 inches, 
and at 74 years it barely exceeds 22 inches; thence to the 
13th year there is a regular and somewhat more rapid 
development of these dimensions. From the 12th to the 
13th there is a slight retardation of growth in a great 
number of boys, but after 134 years the chest circumference 
grows quickly, its expansion during the three following 
years being at the rate of about 1} inches per annum. 
The chest growth of girls is much the same as for boys, but 
the circumference is greater at almost every age. 
The chest expansion shows three periods of growth. Up 
to 84 years the development is inconsiderable, rising in 
boys from 525 to 860 cubic centimetres, and in girls from 
820 to 1050 centimetres; from 84 years to about the 13th 
year the increase is rapid and regular, the capacity at 
134 years being 1800 cubic centimetres. After 134 years 
there is still further expansion, so that at age 164 it has 
increased in boys to 2680 cubic centimetres, and in girls 
to 2200. 
Boys have a larger lung capacity than girls from the 
period of puberty onwards, but from the 9th to the 13th 
year the lung capacity of the two is almost identical, and 
prior to the 9th year the comparison is much in favour of 
‘the girls. The observations, however, have not been on so 
extended a scale as to warrant their being implicitly relied 
on. One peculiar feature worthy of attention is the small 
chest expansion of the Australian boys measured compared 
with that of European boys. In Ashby’s and 
Wright’s “‘ Diseases of Children,” the average capacity of 
boys from 5 to 7 years is given as 900 cubic centimetres, 
compared with 690 observed in Sydney; from 8 to 10 
years, 1300 cubic centimetres, compared with 820; from 11 
to 12 years, 1800 cubic centimetres, compared with 1440 ; 
and from 13 to 14 years, 2200 cubic centimetres, compared 
with 1800. The chest circumference and lung expansion 
