Large fishes must have small cuts made in the walls of the abdomen to allow the fluid to properly penetrate. In cases where the specimen is not required for dissection, the removal of the viscera facilitates the ultimate preservation.
If at 'any time it is necessary to throw away a quantity of inexpensive spent liquor which may smell offensively, a small quantity of the crystals of permanganate of potassa will instantly deodorise a large quantity of fluid, and this without adding to it any offensive scent of its own, as in the case of chloride of lime or carbolic acid. The vessel must be afterwards well rinsed out in clean water, as 'the potassa temporarily stains everything in contact a rich purplish red.
Some experiments which I conducted with benzoline incontestably proved to me its valuable properties. I experimented on a Cornish chough — an old specimen, infested with maggots or larvae of the "clothes" moth. I immediately plunged it in benzoline, took it out, drained the superfluous spirit off, and rapidly dried it by suspending it in a strong current of air.
It took but a short time to dry, and, though the feathers were very slightly clotted after the operation, yet, by a little manipulation, explained hereafter, they soon arrived at their pristine freshness, and all the insects which previously infested it were effectually killed. I afterwards found on another specimen — a short-eared owl — two or three larvae feeding on the feathers. I poured a little benzoline over them in situ, and they fell off, apparently dead. I kept them for a day, and by that time they were shrivelled and undeniably dead.
Here, then, we have the two elements of success — a perfect destroyer of insects, and an agent not damaging, but positively beneficial, to the feathers of birds when applied; added to which, is the remarkable cheapness of benzoline. Caution — do not use it near a candle, lamp, nor fire, as it gives off a highly inflammable vapour at a low temperature; it also fills a house with a peculiarly disagreeable odour, finding its way upstairs, as all volatile gases do; so it had better always be used in the workshop or outhouse.
I have just discovered — and feel very "small" that I did not do so before — that benzoline perfectly preserves birds "in the flesh" for a considerable time. I tried it on a razorbill (Alta torda, L.), which I placed in a "preparation" jar, filled with common benzoline at l s. per gallon. The bird was simply cut under the wing to allow the benzoline to penetrate, and was left for three weeks; at the end of which time it and taken out, cleaned in plaster (as described in Chapter XI.), and made a most excellent taxidermic object! The advantages of this to the overworked professional are obvious.
In very severe cases I have used turpentine ("turps") with excellent effect; in fact, as a destructive agent for insects, I prefer it to benzoline, having now mastered the hitherto fatal objections to its use on birds' skins. For the skins of mammals there is nothing to beat it. This will be enlarged on in the chapter on "Relaxing and Cleaning Skins."
In thus speaking of benzoline and turpentine as agents in the destruction of insect plagues, I mean, of course, that the specimens should be plunged into, or have poured over them either benzoline or turpentine. This seems to have been lost sight of by some former correspondents of mine, one of whom writes —
"In your toxicological section, I do not find any opinion on atmospheric poisoning of acari, etc..
"If not giving you too much trouble, I should be glad to know whether you think spirits of turpentine would be efficacious if allowed to evaporate in a case of birds in which moths have lately shown themselves.