620 Analyses of Books. | October, 
subject, for, although already published, it is still unknown to 
many microscopists, and little heeded by many more. 
The chapter on mounting and preparing objects includes all 
the most recent processes in the time that has elapsed between 
the publication of the present and the former edition. The im- 
proved processes of section cuttings, aided by the use of reagents 
for staining, hardening, corroding, and in other ways rendering 
obscure structures more readily visible, have quite revolutionised 
this department of microscopical science. The student will find 
here an account of nearly all the best processes in use, and 
references to many others not included in the book. This 
chapter concludes with some valuable hints on collecting. The 
author’s experience in the Porcupine ” and “Challenger” 
expeditions renders him a reliable guide on all matter relative to 
marine collecting. 
The remaining two-thirds of the work is occupied, as of old, 
with an account of the minute structure of the vegetable and 
animal kingdoms. In some departments — for instance, the 
Foraminifera — Dr. Carpenter is probably the greatest living au- 
thority. The result of his researches on Eozoon are given at 
some length. The descriptions throughout are interspersed 
with the mode of carrying on the needful observations where 
necessary to supplement the instructions given in the earlier 
portion of the book. These notes in special modes of observa- 
tions are of great value, as microscopists, in describing the 
results of their observation, too often take it for granted that the 
means by which these results are attained are known to every- 
one, while, as is often the case, special apparatus or treatment 
has been necessary to ascertain some most important faCt. 
On the vexed question of aperture of objedf-glasses Dr. Car- 
penter expresses a very decided opinion. While admitting the 
value of well-correCted objectives of the large apertures recently 
attained, for a certain set of purposes, he cannot endorse the 
statement of some enthusiasts, that with such excessive apertures 
alone can structure be truly made out. Evidence is certainly in 
Dr. Carpenter’s favour ; for some of the most important disco- 
veries of modern times have been made with objectives of high 
power and comparatively small aperture, and the value of an 
amount of great depth, not to be had in combination with very 
great aperture, has often to be considered. 
It is to be regretted that, in this and one or two preceding edi- 
tions, space could not be found for the introductory chapter which 
formed so interesting a commencement to some of the earlier 
editions. 
