MUS 
tic aciil in the laboratory is very consider- 
able ; but in medicine and the arts it is em- 
ployed only in the form ot a muriate, or 
combined with some salifiable base. No- 
thing, says Mr. Aiken, takes oft the crust of 
oxide of iron, whicli is sometimes found ad- 
hering to glass vessels, so safely and quickly 
as a little warm dilute muriatic acid. 
MU.RRAYA, in botany, so named in 
honour of Joseph Andrew Murray, profes- 
sor of medicine and botany at Gottingen, 
a genus of the Decandria Monogynia class 
and order. Natural order of Aurantia, 
Jussieu. Essential character: calyx five- 
parted ; corolla bell-shaped, with a nectary 
encircling the germ; berry one-seeded. 
There is but one species; viz. M. exotica, 
ash-leaved Murraya, a native of the East 
Indies. 
MUS, the rat, in natural history, a genus 
of Mammalia of the order Glires. Generic 
character : fore- teeth, upper, wedge-formed ; 
three grinders almost always each side each 
jaw ; clavicles in the skeletons. There are 
forty-six species, of which we shall notice 
the following : 
M. zibethicus, or the musk rat, is as large 
as a small rabbet, and very common in Ca- 
nada; aud resembles the beaver in the 
shape of its body, and in its instincts and 
character. It lives in society, and con- 
structs its habitation with great skill and 
art, about two feet in diameter, and stuc- 
coed within with particular neatness, on the 
border of some lake or stream. On the 
outside it is covered with a matting of rushes, 
compacted with great closeness, to preclude 
moisture. These animals live on roots and 
herbage, rvhich, however, they do not store 
up in their houses, but make excursions for 
as they are demanded during the winter ; 
in summer they make long progresses in 
paii-s. They have attached to them a strong 
odour of musk ; and walk and run with great 
awkwardness; are easily tamed, and highly 
valued for their fur. 
M. decumanus, or the Norway rat, is 
imagined to have been imported into Eu- 
rope from India, and in this country has al- 
most extirpated the animals known by the 
name of black rats, which formerly univer- 
sally abounded in it. It subsists not only 
on grain and fruits, but frequently attacks 
poultry and rabbits, as well as various other 
animals. It is about nine inches long in the 
body, and nine more in the tail ; will swim 
with considerable ease; is in the highest 
degree prolific, producing occasionally even 
eigliteen young at a time, and breeding not 
MUS 
unfrequently three times a year. Itisbold, 
fierce, and voracious. When closely fol-, 
lowed, it tunis on its enemy, and fastens on 
him with its sharp and irregular teeth, in- 
flicting a wound which it requires consider- 
able time to heal. The depredations coiut. 
mitted by these animals are calculated at an 
almost incredible amount. Their extreme 
fecundity, and their means of eluding the 
hostility of man in a thousand instances, 
render them one of the most serious nui- 
sances. They plunder pigeon-houses, gra- 
naries, warehouses, and every species of 
stores convertible to food, with incessant 
rapacity and perseverance. They carry off 
sometimes considerable quantities of grain, 
and store it in their holes. They wage, 
however, most dreadful war on one ano- 
ther, and the weak become uniformly the 
victims of the strong. The large male 
I at, which generally lives in a mischievous 
and malignant solitude, is the most fatal 
enemy to his species. Dogs, cats, and 
weasels combine their efforts with those of 
man to produce their extirpation ; but no- 
thing appears capable of counteracting their 
rapid multiplication, and producing security 
from one of the most predatory and annoy- 
ing animals which infests the society of 
mankind. Their sagacity is very extraor- 
dinary ; and snares laid for them, after one 
victim has been known to fall by them, are 
generally laid in vain. The surest method 
of destroying them is by mixing poison with 
some favourite food, and laying it in their 
way. See Mammalia, Plate IX. fig. 4. 
M. rattus, or the black rat, is consider- 
ably smaller than the former, and in this 
country has been nearly annihilated by it. 
Its habits are almost precisely similar to 
those of the former. It is sr.pposed to come 
from the same countries ; but is thought to 
be a native of North America also. It is 
reported by travellers, that in various parts 
of Germany it is sometimes taken and do- 
mesticated, and, having a bell put round its 
neck, is thus almost invariably found to 
alarm all others of its species from the vi- 
cinity. 
M. amphibius, or tlie w-ater rat, inhabits 
both the temperate and cold climates of 
Europe and Asia, frequenting the banks of 
rivers, in which it buri'ows. It subsists on 
frogs, and roots and other vegetable sub- 
stances ; swims with great speed, and can 
remain under water a considerable time. 
It is more thick and short in its body than 
several other species. It is never known to 
infest houses. 
