1891] Botany. 379 
well as for tissue designed for histological purposes. The fresh material 
is put in 50 per cent. alcohol, and then the strength of the alcohol is 
gradually increased until it is at. least 80 per cent. A very effective 
way of hardening-is to place the material in a straight glass vessel, 
such as a straight beaker having a membrane of chamois-skin for a 
bottom, This is placed in another jar. This makes a vessel within a 
vessel. The outer one contains 95 per cent. alcohol; the inner con- 
tains the material and just sufficient 50 per cent. alcohol to cover it. 
Gradually the alcohol in the inner vessel will become stronger, until it 
is sufficiently strong to preserve the tissue, This is Schultze’s appara- 
tus. ardening in this way saves alcohol and time. Where material 
is changed from weaker to stronger there is always left over a consid- 
erable quantity of alcohol too weak to use for permanent storage. Where 
the Schultze apparatus is used, the spirit in which the material is when 
hardened is strong enough to preserve it indefinitely. We store our 
hardened material in ordinary fruit jars. It is perfect in all respects 
except color, the loss of which is more of an advantage than disad- 
vantage. The tissue is clear and cuts smoothly. By keeping it slightly 
moistened with the preserving fluid while dissecting, it preserves its 
shape as long as desired. It is less pulpy than fresh tissue, and much 
more manageable than dry. 
The sets of mounted specimens are permanent, and with careful 
usage will last a long time. The supply of alcoholic material can be 
replenished from time to time at slight expense 
It is of great value to have a set of microscopical slides on which 
are mounted sections of the ovary so cut as to show the insertion of 
the ovules ; also their parts and their arrangement. This is a subject 
of much importance in the study of systematic botany, and one in- 
volved in considerable difficulty. The fresh tissue of ovules is delicate, 
and by hardening in alcohol, imbedding, and making permanent micro- 
Scopical mounts, a very profitable and interesting course of study may 
be arranged. If any teachers have occasion to use specimens for study 
during the season when flowers are not in bloom, they will find this 
method worth trying.—W. W. Row Ler, Cornell University. 
A Field Manual of Botany.—It is announced again that there 
will soon be issued a special edition of Gray’ s Manual for field use. 
It will be printed on thin French paper, with narrow margins. It will 
be bound in full leather, lintp, and cut flush, very much like a foreign 
guide-book, The price will be two dollars, which is but a trifle more 
than for the ordinary edition. It will prove a useful book to students 
_ and collectors.—Cuaries E. BESSEY. 
