The Collection of Fishes 161 
a large amount of the fluid. The specimens also require much 
less attention. An incision should be made in the (right) side 
of the abdomen to let in the fluid. The specimen can then be 
placed in formalin. When saturated, in the course of the day, 
it can be wrapped in a cloth, packed in an empty petroleum 
can, and at once shipped. The wide use of petroleum in all 
parts of the world is a great boon to the naturalist. 
Before preservation, the fishes should be washed, to remove 
slime and dirt. They should have an incision to let the fluid 
into the body cavity and an injection with a syringe is a useful 
help to saturation, especially with large fishes. Even decay- 
ing fishes can be saved with formalin. 
Records of Fishes—The collector should mark localities 
most carefully with tin tags and note-book records if possible. 
He should, so far as possible, keep records of life colors, and 
water-color sketches are of great assistance in this matter. In 
spirits or formalin the life colors soon fade, although the pat- 
tern of marking is usually preserved or at least indicated. A 
mixture of formalin and alcohol is favorable to the preserva- 
tion of markings. 
In the museum all specimens should be removed at once 
from formalin to alcohol. No substitute for alcohol as a per- 
manent preservative has been found. The spirits derived 
from wine, grain, or sugar is much preferable to the poisonous 
methyl or wood alcohol. 
In placing specimens directly into alcohol, care should be 
taken not to crowd them too much. The fish yields water 
which dilutes the spirit. For the same reason, spirits too dilute 
are ineffective. On the other hand, delicate fishes put into 
very strong alcohol are likely to shrivel, a condition which may 
prevent an accurate study of their fins or other structures. It 
is usually necessary to change a fish from the first alcohol used 
as a bath into stronger alcohol in the course of a few days, the 
time depending on the closeness with which fishes are packed. 
In the tropics, fishes in alcohol often require attention within 
a few hours. In formalin there is much less difficulty with 
tropical fishes. 
Fishes intended for skeletons should never be placed in 
formalin. A softening of the bones which prevents future 
