INTHODUCTION. 
3 
premises were removed, for the purpose of amiiliilatiog the 
rats, he found that where the corners of bricks protruded, 
so as to obstruct) them in their runs, they had actually 
gnawed them off, and thus obtained a free passage. I have 
also met with several instances wherein they have not only 
eaten through zinc drain-pipes, but leaden beer and water 
pipes. ISTeither are even gas-pipes free from their depre- 
dations. The following instance was lately recorded in the 
Manchester Guardian " : — 
" A circumstance has been communicated to us this week 
by Messrs. J. P. and E. Westhead and Co. of this town 
(Manchester), which shows the serious risks of explosion, as 
well as great annoyance from the smell of escaping gas, may 
arise out of the ravages of rats. In the new warehouses of 
that firm in Piccadilly, some of the gas-pipes are placed, as 
usual, between the floors and ceilings beneath, and an un- 
pleasant smell of gas having been perceived, an examination 
was instituted into the condition of the pipes, when it was 
found that some of them had been gnawed through by rats, 
and in two of them there were holes large enough to permit 
an escape of gas quite sufficient to cause a most serious and 
destructive explosion. In one case the hole in the side of 
the pipe was equal in size to the width of the pipe itself." 
The writer then states that these facts should be generally 
known, as it may be necessary, in some cases, either to have 
pipes of some harder material than lead, or to case them in 
tin or sheet iron. But to me it seems far more desirable to 
get rid of the rats themselves ; since there are a host of 
other things besides gas-pipes that suffer from their ravages. 
" Yes/' it will be said ; " but how is this to be done effec- 
tually ? " To this, I reply, read my book, and then you will 
ascertain the means. 
I can perfectly understand the surprise, nay, I may say, 
astonishment, created in the minds of some at the Aveight I 
attach to rats ; but this in most cases arises from want of a 
due consideration of the subject. It is certain that rats are 
known to almost every one ; but the local injuries they 
commit are seen only by minute observers. Hence it is, 
that if a few instances of their swarming numbers and 
midnight ravages be collected together, and laid open to the 
b2 
