PROCEEDINGS OP SECTION D. 517 



M. norwegicus only gets to places by occasional chances, and only on 

 big sbips ; so it is always a long time getting there, and then only 

 found in big towns at first. Still, there is no doubt Nos. 8391 and 8392 

 are it." 



This communication is very interesting and very important. Is 

 it possible that the blind flea Typhlopsylla musculi, which does not bite 

 man, is the predominant flea on 31. norwegicus, and hence, when this 

 rat exterminates M. alexandrinus, even though plague occurs in the 

 now dominant M. norivegicus, it cannot reach man ? 



M. norwegicus has apparently only recently reached Perth and 

 Fremantle. In Perth itself it is only occasionally met Math. On the 

 wharves at Fremantle, however, it is the predominant, if not the only, 

 species, though within the town of Fremantle it is again in a minority. 



I have had an opportunity of seeing a few caged Adelaide rats. 

 They all appeared to be M. norwegicus. If this proves to be the pre- 

 dominant species here it may explain why plague has never established 

 itself in South Australia, even though it has been at times exposed to 

 considerable risk. 



We have often had ocular proof in Perth of the climbing powers of 

 M. alexandrinus. This species, we have found, will also live \yell in cap- 

 tivity, as is well known. Some we have had alive for months. They 

 are very interesting pets. They keep themselves spotlessly clean, and 

 are continually washing their faces and ears wath their hands, much as 

 we do. They sit up, holding a biscuit in two hands and nibbling the 

 middle. They are very brave, and sometimes very savage. One we 

 had, seemed to " run amok " among his fellows, killing a number of 

 others in the same cage, irrespective of sex. It is very interesting to 

 see two of them fighting. They stand up in front of each other holding 

 their arms half bent, and " chirping " or " snarling." Then suddenly 

 one makes a dash, and tries to bite the other's neck. Sometimes a large 

 rat — like a big schoolboy — will stand in front of and bully a smaller one, 

 the latter complaining in low, piteous accents. The reflex jump to any 

 sudden noise is nearly always very marked, and apparently quite un- 

 controllable. A rat may be eating or drinking at the time, and will 

 always jump at the sound, but as often as not without leaving the spot 

 he is on, or even interrupting the operation in progress — probably 

 because they have no hiding-place to which to run. 



THE DISEASES OF RATS IN WESTERN AUSTRALIA. 

 Rats, as everyone knows, have suddenly sprung from comparatively 

 innocuous, if not directly helpful, vermin into one of the most deadly 

 enemies to man. I refer to the transmission of epidemic plague. From 

 biblical times downwards their connection with this disease has been 

 noticed ; but it rested with latter-day epidemiologists — and at their 

 head Dr. Ashburton Thompson and Dr. Tidswell, of Sydney — to show 

 that they were not only more or less innocent victims to it, but in 

 reality the chief means of its disposal almost throughout the globe, 

 and of its survival in many places when once introduced. To those, 



