240 THE ANTARCTIC MANUAL. 
This might perhaps be done without too much expenditure of 
spirits, if the supply be a limited one, by preserving some of the 
duplicates in formaldehyde, or formol, as it is frequently called. This 
fluid, which is strongly recommended for the preservation of some 
groups of invertebrates, is invaluable from the fact that, such as it is 
supplied by the trade, it may be diluted with 25 volumes of water, 
But the results, so far as fishes are concerned, have not proved satis- 
factory. It has these drawbacks :—1. That it hardens the tissues, 
stiffens the fins, practically “sets” the specimens, and renders them 
brittle when manipulated ; 2. That the fluid is more or less unstable, 
and, when exposed to light, produces an acid solution, the effects of 
which may be actually to decalcify the bony tissues. I therefore 
strongly recommend the use of spirit of wine at 20° over proof for 
the preservation of the first set of specimens, formol to be employed 
only for duplicates if reasons of economy should at all warrant 
its use. 
Sharks may be found in some abundance. Suffice it to say that 
our knowledge of them is still very incomplete. Their preservation 
in brine should offer no difficulty in a cold climate ; large specimens, 
that is, over 4 feet, to be preserved as skins, rolled up over the head, 
which may be left intact, and packed in barrels filled with salt. 
