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tight. Now the process I am about to describe, I consider 
does-away with both of these difficulties, whilst it is at the 
same time readily put in practice. 
If the animal dealt with be a tolerably large one, or rather 
if it be one possessing an Odontophore of such a size that it 
can be readily dissected out by means of knives, such a pro- 
ceeding is put in practice, and that organ roughly cut away 
from the surrounding tissues, without any attempt being 
made at the same time to render it clean. But if the indi- 
vidual be a.small one, as for instance our small native 
Littorina, no. dissecting by means of knives or other instru- 
ments is attempted, but the animal whole, or even with the 
shell attached, in such cases where the animal has withdrawn 
deeply into the shell, as-is commonly the case with specimens 
preserved in alcohol, and with which this process works 
admirably, or, as in the cases first mentioned, the uncleaned 
odontophore is placed in a test-tube, and there is poured 
upon it sufficient of Liquor Potasse to cover it to a depth of 
at least half an inch. In some cases where the organ is very 
delicate, it may be necessary to use a weaker solution than 
the officinal Liquor Potassw, or the odontophore is merely 
permitted to soak in the cold solution instead of using any 
heat. Or there may be, and in fact often are cases where a still 
stronger solution is required, but this point can only be 
ascertained by trial. After the odontophore has thus been 
immersed in the alkaline solution, if time permits, it is 
allowed to soak therein for some time, varying from a day 
to several weeks, but if the preparation is to be finished 
rapidly, it may be heated and boiled for a few minutes. 
With alcohol-hardened specimens I find it best to boil the 
liquid, but with fresh material it is not always so. safe, as 
injury is often done by so proceeding. The action of the 
alkali is to dissolve everything but the shell, odontophore 
and a few shreds. of muscular fibre, converting everything 
else into a soap. Now the contents of the test-tube are 
poured into a large vessel of clean water, and what is not 
dissolved, permitted to settle. The odontophore can then be 
easily distinguished and taken out by means of a dip-tube 
