THE BROWN RAT. 
11 
piebald young ones, which are pretty little creatures, and as 
tame as kittens. He says, " they breed six times in the 
year ; and when the young are two weeks old, the mother 
is again pregnant. The young ones will breed at four months 
,old." He mentioned one female which bred so fast that 
she died from sheer exhaustion. But the natural powers 
of the rat for breeding are so great, that I believe few 
animals, if any, in the creation can equal them. He also 
informs me that these animals are subject to no diseases, 
except when kept in a dirty cage for any length of time ; 
and then, like ferrets, they are subject to a kind of mange ; 
but cleanliness and good diet will soon cure them. The 
most he has had in a litter were thirteen, and not a dark hair 
among them. 
Now this does not favour the general opinion of natu- 
ralists, or of Mr. Richardson, as to the albino or white rat 
being an accidental variation from the brown or black rat, 
because it is a well-known fact to all breeders, either of 
beasts or birds, that any young one, which may accidentally 
vary in colour from the rest, will in breeding-time revert to 
the original stock. So far from doing this, the albino, or 
white rat, will breed for generations together without 
varying in colour. Consequently I am led to believe that 
they are a bond fide species j but this I will most humbly 
leave in the hands of profound naturalists to investigate and 
decide. 
The Brown Rat {Mus decumanus, Linnaeus). 
We now come to the common Brown rat, or, as BufFon 
and Cuvier style it, the surmulot. To me it is of little 
import by what name they call it. This is the animal 
against whose ravages the present work is directed. Its 
natural characteristics are so well known that a description 
seems almost superfluous. Nevertheless, for the greater 
completion of my work, I will give its colour, parts, and 
proportions, as described by Linnseus. 
The brown rat is the largest species of the genus that 
occurs with. us. Its body is rather elongated and full, the 
limbs short and moderately strong, the neck short, the head 
of modei-ate size, compressed, and rather pointed ; the ears 
are short and round, the tail long, tapering to a point, and 
