BEALE, ON THE MICROSCOPE. 43 
rendered clear, we will not here detail them. Nor, with 
regard to our limits, can we enter upon several other points dis- 
cussed in this valuable chaper, which is essential to be studied 
by all who would make themselves acquainted with the va- 
rious opinions entertained upon the general homologies of the 
Mollusca. 
Having thus noticed, at considerable length, the more 
general part of Professor Allman’s work, we can further merely 
state, that it afterwards proceeds: 1. To the history and bib- 
hography of the subject ; 2. To the geographical distribution 
of the Fresh-water Polyzoa; with respect to which, it is re- 
marked as a surprising circumstance that not a single species 
has been found beyond the limits of the north temperate 
zone, not one having been recorded as occurring south of 
the Mediterranean in the old world, or of Philadelphia in the 
new. And this limited distribution is the more remarkable, 
since some species are found at an elevation of 6,500. 
The succeeding portion of the work is devoted to an 
account of the various genera and species. 
How to work with the Microscope. By Lioneu 8. Beare, 
M.B., F.R.S. London: John Churchill, 
Few men have worked more diligently and successfully 
with the microscope than Dr. Beale, and none have more 
claims to be heard on its uses and the methods of its appli- 
cation. Although we have had many works devoted to the 
microscope, to explanations of its structure, and the objects 
it investigates, we think with Dr. Beale that a book with a 
more thoroughly practical aim was really a desideratum. It 
is this hiatus in our literature which Dr. Beale has attempted 
in the present work to fill up. The imstruction conveyed is 
in the form of lectures, which were, in fact, delivered by the 
author during the winter session of 1856-7. He offers the 
following apology for his little book : 
“An earnest desire to assist in diffusing a love for microscopical inquiry, 
not less for the pleasure it affords to the student, than from a conviction of 
its real utility and increasing practical value in promoting advancement in 
various branches of art, science, and manufacture,—a wish to simplify as 
far as possible the processes for preparing microscopical specimens, and the 
methods for demonstrating the anatomy of different textures,—and the 
