40 J. B. CLELAND. 
the utmost, in human beings, an accidental case or so might 
occur under these circumstances, conveyed by fleas actually 
leaving the sick introduced rats or by some other fortuit- 
ous means. 
It is, therefore, of very considerable importance to know 
the distribution in Australia of these rats and mice. As 
regards the latter, they are so easily transported’ in mer- 
chandise of various kinds, by rail, team or sea, that they 
may be considered as practically universally distributed 
throughout the continent wherever man has his dwelling— 
even the temporary shelters of camps. Thus I remember in 
1907, when investigating Surra in camels in Western Aus- 
tralia, when we were camped for several months 60 miles 
inland from Port Hedland, and with no town nearer than 
this port on one side or Marble Bar, equally far away, on 
the other, that several mice, almost certainly the house 
mouse, were found to have accompanied us, probably in 
forage. Yet there was no bush station house within many 
miles. Spencer and Gillen mention that the common mouse 
has reached the centre of Australia. The recent rapid ex- 
tension of the wheat belt also favours its spread by giving it 
abundant food. Mice, however, though capable of being in- 
fected by plague and suffering therefrom when the rat 
population is suffering from the epizootic, are not considered 
responsible for the general spread and maintenance of the 
disease. Doubtless, however, if plague gained access to 
them when present in such countless hordes as were re- 
cently witnessed in this and neighbouring States, an epi- 
zootic might be started and human beings infected, provid- 
ed, as regards the first occurrence, that fleas were on them 
capable of conveying the plague bacillus from mouse to 
mouse, and as regards the second occurrence, that such fleas 
would also bite man. Amongst samples of the mice from 
+“Across Australia,’ I., p. 166. 
