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BULLETIN to a new book in technique for beginners in micro- 
scopic botany, by W. Behrens, which has recently been issued 
in Germany. The first eighty-three pages discuss, in a very 
readable manner, and with excellent illustrations, the simple and 
compound microscopes, the polariscope, spectroscope, methods of 
measuring, of drawing and photographing microscopic objects. 
In order to present these subjects intelligently to the reader, 
the book is introduced by a discussion of the phenomena of light. 
The lenses and objectives are well illustrated, both in piece and 
in section, so that any one can easily understand their workings. 
This is equally true of all the accessory apparatus. The 
remaining one hundred and twenty-five pages discuss, fully 
enough for all beginners, the better methods of preparing, hard- 
ening, staining, and preserving materials for microscopical exam- 
ination. 
_ Something of the care with which the minor details are looked 
after may be judged from the fact that over ten pages are 
devoted to careful directions concerning the selection and sharp- 
ening of knives, and methods of holding the same in free-hand 
cutting. 
Directions are given for collecting, cultivating when necessary, 
hardening, fixing, bleaching, and macerating different kinds of 
tissues and material for the microscope. Also full instructions for 
making permanent mounts of various kinds. 
Methods of embedding in glycerine-jelly, gum-arabic, cel- 
loiden, paraffin, and transparent soap, are all fully and explicitly 
given. Even some of the foreign bodies which are most likely 
to find their way into microscopic preparations, are discussed and 
illustrated. 
The merits of this book are, first, that it gives the student 
directions about many minutiz not generally spoken of in such 
books, but on points always sure to trouble the learner. To il- 
lustrate : on the use of the fine adjustment, which even advanced 
students sometimes neglect to their great disadvantage; or on 
the manipulation of the light for different effects, often not under- 
stood by even those who are far advanced in work. The in- 
struction on this point, i. e. the positions of the mirror, the 
handling of the diaphrams, and the parts of the Abé condenser, 
