NOTES ON A GREAT VISITATION OF RATS. 193 
The following papers were read :— 
NOTES ON A GREAT VISITATION OF RATS 
IN THE NORTH AND NORTH-WEST- 
ERN PLAIN COUNTRY OF QUEENS- 
LAND, IN 1869 AND 1870. 
BY 
EK. PALMER, M.L.A. 
In the case of feral animals, the number of a particular kind 
frequenting any one spot seems to be subject to periodical varia- 
tion. It is as if the latent force of over-reproduction, inherent in 
the lower forms of animal life, only demands that the checks be 
removed or loosened, and when this has happened immediately 
the power asserts itself. In illustration of this statement I will 
describe what, in so much as it has happened recently, is perhaps 
well-known to many, the extraordinary and sudden increase in 
numbers of an indigenous rat in the western and north-western 
plains, from the heads of the Flinders and Cloncurry northwards, 
in the years 1869-70. 
Where these rats came from is a mystery. About the middle 
and towards the end of 1869 they were first noticed ; principally 
by the action of the black-boys in going out on the plains and 
bringing in scores of them, in an hour or two, for roasting as 
food. January and February, of 1870, were months of continu- 
ous rain, ending in the largest floods ever known—the waters 
covering the country for many miles. 
As a result of this exceptional season of 1869-70 there was an 
exuberance of vegetation generally, and the presence of the pea- 
bush, (Sesbania cegyptiaca), all over country where it had 
not been known before. This plant attained to a height of eight 
to ten feet, and grew so close that it was almost impossible to make 
one’s way through it ; indeed so dense was it that frequently 
