THE COMMON MOUSE. 331 



from a single couple a great number are produced in the course 

 of a few months. Aristotle says, that in a very short period 

 no less than a hundred and twenty mice sprang from a single 

 female which he had confined in a closed vessel filled with 

 grain. 



The zoological dealers sell cross breeds between the brown 

 mouse and the white variety. I have seen at one shop in 

 London some very beautiful tortoise-shell mice, for which the 

 price was half a crown each. Mr. T. W. Edwards showed me 

 recently a very extensive collection of living mice, many of 

 which were cross-breeds mottled with black and white. In M. 

 W. F. Edwards's Caracteres des Races Humaines (1829), p. 25, it 

 is, nevertheless, stated that M. Coladon, chemist at Geneva, 

 tried a long course of experiments on this subject, always 

 coupling a grey mouse with a white one, and found that the 

 offspring were invariably either entirely white, or entirely grey, 

 like one or other of their parents 5 there was no mixture of 

 colour. 



THE COMMON BROWN RAT.* (Mus Decumanus, Pall.) 



It is well known that the indigenous black rat (Mus rattus) 

 of Great Britain, has become nearly extirpated by the present 

 and more powerful species, which appears to have been acci- 

 dentally introduced from Persia. Pennant states that the brown 

 rats arrived in England about 1728, and in Paris about twenty- 

 three years after that period ; but a modern writer asserts that 

 * Improperly called the Norway rat. 



