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IN USE AT THE ROYAL BOTANIC GARDEN. 227 
animals." Marpmann® has recommended sodium-fluoride, 2, 3, 
and 5 per cent. solutions in water. The bifluoride is also recom- 
mended. It possesses greater antiseptic properties than the 
fluoride. “It is not, in dilute solutions, directly poisonous, and 
so is pleasanter to work with than formol or sublimate 
I have made experiments with a number of solutions. In 
all cases the colours of plants fade or are destroyed. The 
plants become soft and flaccid, and in solutions of less than 10 
per cent. fungi may appear on the sariats of the fluid, and on 
the submerged material also. 
The corroding action of the bifluoride on glass, even of com- 
paratively weak solutions, prohibits its use as a final preservative 
in glass vessels. 
RB. PRESERVING BY DRYING. 
DRYING - IN AIR 
The following are the methods employed in dealing with the 
different classes of material mentioned. 
a. Specimens of branches and twigs which are too large to be 
preserved in a fluid medium are dried by hanging them in a dry 
room, or, if the specimen is not too large, it is placed in a venti- 
lated box to protect it from dust, or sand is run around it and the 
specimen dried in sand (see Drying in sand). Where the leaves 
are known to fall readily after drying the specimen is placed 
for a few minutes in boiling water before the drying process is 
commenced. 
é. Specimens of woods and the like. Logs of wood which are 
to be dried and afterwards sawn or prepared as specimens of 
woods are placed in any dry well ventilated store. The drying 
should be slow and the temperature even. It is not enough that 
the store should be warm; unless well ventilated, the wood is 
liable to rot; again, if the drying is too rapid, the cracks produced 
areconsiderable. The logs are laid on their sides, freely expos- ~ 
ing both cut ends. Where it is wished to preserve the bark, the 
logs are laid upon straw or brown paper. To keep free from 
cracks any special part of the bark I have found it an advantage 
to make longitudinal incisions at a parts of the circumference. 
asians Annual Report for 1899, p. 2 
rpmann, Zeitschrift fur angewandte “Mrkroskopié, 1899, p. 33. Central- 
blat fur Bekteriologie und Parasitenkunde, 1899, Vol. 25, p. 309. 
