746 



THE NATURE BOOK 



A BLACK RAT. 



Probably a melanistic variety of the Common Brown 

 Decumanus, the ears being too small and the nose too 

 Mils Ratttis. 



Rat, Mils 

 blunt for 



according to the Russian naturalist, Pallas, 

 in 1727. A few years later he arrived in 

 England, ship-borne from some unknown 

 port, and, in a hundred years' time, 

 had so taken advantage of the British 

 carrying trade as to have overrun the 

 world. Wherever exigencies of space, 

 or scarcity of food, have brought him 

 into direct conflict with the Ratton, the 

 weaker species has gone to the wall. 

 There is no interbreeding between them, 

 and the ultimate fate of the Ratton at 

 the hands of the Rat is complete exter- 

 mination. It is probable that the Ratton 

 of this country — the old English Black 

 Rat of two hundred years ago — was com- 

 pletely exterminated. Both Rats and 

 Rattons, however, are born sailors (how 

 otherwise can we account for their sur- 

 vival through rough weather when the 

 alternative to being smothered in grain 

 or copra, is being drowned in bilge ?), and 

 it is to the accidental settlements of alien 

 Rattons in our seaports (Eondon being 

 the chief, though most stringent pre- 

 cautions are taken to prevent Rattons 

 getting outside the docks) that we owe 

 the periodical rediscoveries of the " Old 

 English Black Rat." 



About ten years ago, in company with 

 Mr. H. C. Brooke, to whom the credit 

 of first distinguishing between the Blue 

 and Black Rattons, and the discovery 

 of the Brown Ratton in this country, 

 is certainly due, I investigated the dis- 



tribution of Rattons in north- 

 west Kent. It was well known 

 to us that they had existed for a 

 long time previously in Woolwich 

 Arsenal — indeed, I had been 

 informed by one of the oldest 

 employees there in 1888 that 

 they (Black Rats) " had troubled 

 him ever since he could re- 

 member " — but we were hardly 

 prepared to find a flourishing 

 colony of Brown, Black, and 

 Blue Rattons so far outside the 

 Arsenal gates as Welling. It was 

 from experiments with specimens 

 from this locality that I satisfied 

 myself that Black and Blue 

 Rattons interbred with each 

 other, but would not interbreed 

 with the Common Brown Rat. 

 Does of all three varieties were 

 very scarce — indeed, I never secured a 

 Brown Ratton doe at all, nor did I suc- 

 ceed in mating a Brown Ratton buck 

 with either a Black or a Blue doe. The 

 shyness and timidity of all the Rattons 

 which passed through my hands was in 

 remarkable contrast to the bold resource- 

 fulness of the Common Brown Rat. A 

 fastidious cleanness was perhaps their 

 most engaging feature — rather than endure 

 a week-old nest they would sleep on 

 bare boards. In view of the close con- 

 nection between Rattons and plague, a 

 disease which is presumably engendered 

 under peculiarly insanitary conditions, 

 this fact is curious. 



It has been conclusively proved by 

 investigations in India that Rattons are 

 highly susceptible to plague. In a paper 

 read before the Bombay Natural History 

 Society {Journal, vol. xvi. pt. 2) Captain 

 Liston, of the Indian Medical Service, de- 

 fines plague as a " rat disease," and classes 

 it, by reason of its being readily communi- 

 cable to man, in the same category as 

 anthrax, glanders, and hydro]^hobia. Infec- 

 tion is accomphshed through the agency 

 of a definite flea, Pulex Cheopis, which, 

 though normally confined to Rattons, 

 will, under stress of hunger, desert its 

 dead or dying host, and fasten, with its 

 stomach full of germs, on the first new 

 host which offers. Pulex Cheopis has 

 definite anti])athies. He shuns the light ; 

 he dishkes oil and tobacco. The danger 



