60 MAX HENRY. 
quent maintenance in the affected areas, it is impossible 
to say. 
The decrease in the prevalence of the disease is due 
partly to natural causes, and partly to buman action. The 
disappearance of Anthrax in many districts was not due to 
action on the part of man, and no explanation can be offered 
as to why it ceased to exist and yet persisted elsewhere, 
save that natural conditions were unsuited to it, but its 
control elsewhere, the prevention of its spread and the 
gradual diminution of the affected area must, to a large 
extent, be ascribed to definite action taken against it. 
These measures were, vaccination, the destruction of 
carcases by burning, and quarantine of affected flocks and 
holdings. There is, as a rule, a tendency to overrate the 
comparative value of vaccination as opposed to the other 
measures adopted, and to leave entirely out of account 
those natural but unknown factors which have unquestion- 
ably greatly influenced the incidence of Anthrax in Aus- 
tralia. For it has to be noted that these factors were 
evidently in existence, not only in New South Wales but in 
Victoria, and, if the evidence of Gordon is to be accepted, 
to a still greater extent in Queensland. Other factors 
which have influenced the incidence of Anthrax have been 
(1) the substitution of farming for grazing in many of the 
worst Anthrax localities, (2) the subdivision of farms and 
stations so that less country became contaminated. 
That this is so is plainly obvious from the history of the 
disease, in spite of Norris’ statement before the Depart- 
mental Committee that ploughing operations would tend to 
increase the incidence of Anthrax. Whether the evidence 
in support of such opinion is of value or no, or whether it 
is true, it is quite evident that other factors involved in 
the change from grazing to farming more than counter- 
balance whatever tendency in that direction may exist. 

