162 The Collection of Fishes 
exact studies of the bones is sure to take place. Generally 
alcohol or other spirits (arrack, brandy, cognac, rum, sake 
“vino’’) can be tested with a match. If sufficiently concen- 
trated to be ignited, they can be safely used for preservation 
of fishes. The best test is that of the hydrometer. Spirits 
for permanent use should show on the hydrometer 40 to 60 
above proof. Decaying specimens show it by color and smell 
and the collector should be alive to their condition. One rot- 
ting fish may endanger many others. With alcohol it is neces- 
sary to take especial pains to ensure immediate saturation. 
Deep cuts should be made into the muscles of large fishes as 
well as into the body cavity. Sometimes a small distilling 
apparatus is useful to redistil impure or dilute alcohol. The 
use of formalin avoids this necessity. 
Small fishes should not be packed with large ones; small 
bottles are very desirable for their preservation. All spinous 
or scaly fishes should be so wrapped in cotton muslin as to 
prevent all friction. 
Eternal Vigilance.—The methods of treating individual 
groups of fishes and of handling them under different climatic 
and other conditions are matters to be learned by experience. 
Eternal vigilance is the price of a good collection, as it is said 
to be of some other good things. Mechanical collecting—pick- 
ing up the thing got without effort and putting it in alcohol 
without further thought—rarely serves any useful end in science. 
The best collectors are usually the best naturalists. The col- 
lections made by the men who are to study them and who are 
competent to do so are the ones which most help the progress 
of ichthyology. The student of a group of fishes misses half 
the collection teaches if he has made no part of it himself, 
