90 ON THE PREVALENCE OF CANCER IN AUSTRALASIA. 



Afie. 



Cancer is pre-eminently a disease of middle-aged and aged 

 people, though its occuiTence among young people is by no 

 means very rare. When affecting individuals before 40 years 

 of age it is generally distinguished by its more malignant and 

 rapid course. Sarcomata, the other class of malignant tumours, 

 attack with predilection persons upwards from 20 years, whereas 

 children and aged people are not so liable to this form of new 

 growth. 



Compared with this experience in European countries, we 

 find the following results in Australia. 



A relative immunity from the liability to malignant new 

 growths is noticeable amongst people below 30 years of age in 

 all the Australian Colonies, though not to the same extent. 

 While in New South Wales and ^^ictoria, for about 25 cases of 

 cancer occurring beyond 30, only 1 occurs below this limit ; the 

 corresponding proportion in Queensland is 1 to 11 among males 

 and 1 to 17 among females. After that age has been reached, the 

 susceptibility to cancer increases rapidly until it becomes greatest 

 in the decenniuui between 50 and 60 years, where it remains 

 stationary for a little while (until 65) and then decreases, though 

 the decrease is less rapid than the increase. An example will 

 illustrate these facts more clearly. Out of a total of 4,700 

 males below 30 years who died in Victoria in 1891, 11 succumbed 

 to cancer, which thus only caused 1 out of 430 deaths. How- 

 ever, in the same year, 1,214 persons died between 50 and 60 

 years, out of" which number cancer was responsible for 124, or a 

 proportion of 1 in 10. The liability to malignant new growths 

 is, therefore, 43 times greater between 50 and 60 than below 30. 

 This remarkable distribution of the susceptibility to cancer 

 amongst the different age-groups is a fact which it is very 

 difficult to explain. The theory generally brought forward which 

 has been accepted, I presume, a fautc dc mieiuv, is that the 

 organism and tissues of young individuals offer a greater resist- 

 ing power to the formation of new growths than old persons. 

 The supporters of the theory of the hereditary transmission of 

 Cancer say the inherited cancer-cell, which is born with the 

 infant, remains inactive during youth and early manhood ; as 

 the person grows older the resistance of the tissue, where the 



