76 ON COLLECTING AND PRESERVING FISHES 
regrettable in the case of the types on which new species are 
founded. 
For the use of those who might feel disposed to collect 
fishes on a larger scale, the following instructions have been 
drawn up. 
All fishes not over two feet in length and, when feasible, 
larger ones also should be preserved in alcohol. Methylated 
spirit (64 degrees over proof) may be used, but should be 
diluted with filtered water to reduce its strength according 
to the nature of the specimens preserved (the strength to be 
tested by means of the hydrometer or alcoholmeter). Fishes 
with naked skin, such as eels and cat-fish, must, in the first 
instance, be placed in spirit not above 10 degrees over proof 
(85 to 40 per cent, of water), to be transferred after a few hours 
to 20 or 25 degrees (80 per cent, water). Ordinary scaly 
fishes must be thrown at once into spirit 40 degrees over proof 
(20 per cent, water), the spirit to be changed after a day 
or two, and a second time if required. Specimens showing 
signs of putrefaction before being placed in spirits should be 
rejected, unless utilised as skeletons. 
In order to accelerate the penetration of the spirit a small 
incision should be made with a scalpel or sharp pair of scissors 
along the mid- ventral line of the fish ; through this opening, 
as well as through the pharynx, strong spirit should be injected 
with a syringe. 
It must be borne in mind that in large and fleshy fishes 
the spirit penetrates very slowly, and in order to prevent 
decomposition of the inner layers of muscle, a few deep incisions 
in the muscular part of the body may be necessary ; these, 
if neatly made, will not seriously damage the specimen. During 
the first period of immersion it is desirable occasionally to turn 
over the specimens and to press them between the fingers, so as 
to expel the blood and mucosities ; the viscera should not be 
removed or injured as they are often required for study. 
Not until the fishes are thoroughly impregnated with spirit 
and free from all signs of decay should they be packed for 
transmission. This is best done by placing them close together 
in a tin or jar, separated by layers of unstained tissue-paper 
or rags, and filling the receptacle with strong alcohol. Every 
