232 REVIEWS. 
tinctness that the beginner should. confine himself to low powers, 
not over one-fourth, until great skill has been obtained by long 
practice. He advises that high-power lenses be sent “to an opti- 
cian ” for cleaning, etc., instead of saying that they should be sent 
to the maker, or at least to a person accustomed to make the same 
class of work: imagine a Ross’ one-twelfth or a Tolles one-tenth 
sent to a local ‘‘ optician” for repairs! Dr. Beale’s directions for 
adjustment of objectives by measuring the covering glass by the 
screw-collar movement, are given without an intimation that good 
performance by lenses made at the present time cannot be obtained 
in this way. The amplifier is named as a means of increasing pow- 
er, but without the caution that some of the cheaper kinds sold are 
not achromatic and are perfectly worthless. Polarized light is 
mentioned, on authority of an obsolete remark by Dr. Beale, as 
an expedient of equivocal value; whereas the medical expert 
finds it of great use in detection of poisons and adulterations, and 
in some other investigations; and the polarizing apparatus is too 
carelessly described as consisting of two crystals of Iceland spar. 
The micro-spectroscope is properly mentioned as a promising 
means of research, and appreciative mention is made of recent 
work in photographing microscopic objects. Finally, the list of 
microscope makers and dealers is rather less than satisfactory. 
In regard to the main body of the book, relating to the practical 
work of the microscope in medicine but little need be said. A 
single expression of unqualified approval will apply to nearly all 
of it. With fewer inaccuracies than usually fall to the lot of first 
editions, such as speaking of ether as “ sulphuric ether,” mention- 
ing ‘fibres of flax from — muslin fabric” ete., an excellent and 
available summary is given of the subjects treated ; adequate study 
being devoted to the literature of the science, and important addi- 
tions being contributed from the author’s experience. The identity 
of the white blood corpuscles with the similar bodies of mucus, 
pus, and saliva, more fully and fairly maintained than by any pre- 
vious authority, is not a theoretical, but a practical question ; as 
students have been for years past perplexed and retarded by their | 
hopeless efforts to distinguish between these bodies, while most mi- 
croscopists of experience were ready to express themselves unfamil- 
iar with any available distinction. The equally practical questions 
of the early detection of phthisis, and the detection of blood dises 
in dried stains, are relieved of much of their former obscurity and 
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