CHAPTER XLIV.

INSECT PESTS AND POISONING.

THE PESTS.--If an island of bare rock should be born to-day in the middle of the Pacific Ocean, and an unpoisoned skin of bird or mammal laid down upon it to-morrow morning, I would wager that _Dermestes lardarius_ would find that skin before sunset. If you were to prepare a skin without poison, and lock it up immediately in the bowels of a burglar-proof safe, not to be opened for six months, at the end of that time you would find it swarming with _Dermestes_. If you ever omit to poison anything in the shape of a vertebrate specimen, be sure your sin and the beastly bugs will find you out.

DERMESTES.--The greatest enemy of the zoological collector and conservator, and one which is world-wide in its distribution, is a small beetle, one-third of an inch in length, commonly called the "bacon beetle." Its flight is rather feeble, but "it gets there just the same." The most common species, _Dermestes lardarius_, is of a dark, dirty-brown color, with a broad, transverse band of dull gray encircling the middle of the body. The imago is not of much consequence as a destroyer, but the larva, a nasty, hairy, brown-backed, and white-bellied abomination half an inch long, and with an appet.i.te like a hog, is the incarnation of all that is pestiferous.

A skull that has been "roughed out" and put away without poisoning will soon be literally swarming with _Dermestes_ larvae, and half-buried with the brown, powdery excrementation they leave behind. If the curator ever sees a fine, brown dust falling in little heaps out of any part of a mounted specimen, he may know that _Dermestes_ larvae are at work.

Not long ago the National Museum was visited by another species of the bacon beetle, _Dermestes maculatus_, a gray-colored variety, beside which his congener seemed harmless and inoffensive. _Maculatus_ was an unmitigated terror. He disdained to graze modestly on the outside of a specimen, as did _lardarius_, but simply began to eat wherever he "lit,"

and went straight in to a depth of an inch or so, as if shot out of a gun.

An unhappy stuffed monkey that once crossed the track of this little fiend had half a dozen neat round holes eaten through the dry skin of his side, and straight on into the hard tow filling for quite an inch. A gimlet could not have done the work half so well. The most ridiculous thing was that this insatiable little monster attacked a plaster cast, and bored it full of holes also! Fortunately for the National Museum, the stay of this highly interesting stranger was of brief duration. He came in 1885, and vanished that same year--so far as my observations went.

MOTHS.--Next in destructiveness are the tiny moths, of which four species are to be fought in the museum and the household. These are the clothes moth (_Tinea flavifrontella_), the fur moth (_T. pelionella_), the carpet moth (_T. tapetzella_), and the grain moth (_T. granella_). The perfect moth is of course by preference a night-flying insect, and very seldom flies in the daytime except when disturbed. The imago is harmless, but the larva--a tiny, white worm no thicker than a pin, and about one-tenth of an inch in length--will soon shave the hair off an unpoisoned elk or deer head more smoothly than you could do it with the best razor ever made. Of course moth larvae are most active and destructive during the breeding season--the warm months from May to October--but in warm rooms they sometimes keep at work all through the winter.

In one sense the moth is the zoologist's most dreaded foe, for the reason that its work is so subtle and unseen. Often the first intimation the victim has of the presence of his enemy is when dusting a favorite head he suddenly knocks off a section of hair half a foot square, exposing underneath the smooth, bare skin covered with fine gray dust. The larvae of the moth attack birds and quadrupeds in one way only, that is by eating the roots of the hair or feathers, and the epidermis. Mounted heads of large ruminant animals are the particular prey of these abominable pests, because they cannot be protected by gla.s.s cases, and are seldom touched save with a feather duster.

In ethnological collections all the garments of skin and leather, and all the textile fabrics are subject to the attacks of the Tineids, as they also are to those of the species to be noticed next.

ANTHRENUS.--Although I have seen this "buffalo bug" try hard to make an impression on mounted mammals, I have not yet seen it do harm except to furs and leather or woolen garments. The adult buffalo bug (_Anthrenus lepidus_) is a tiny, round, brown beetle, with white spots on its elytra, and, as usual, it is the larvae that do the mischief.

SYMPTOMS OF THE PRESENCE OF INSECT PESTS.--Whenever little heaps of brown dust are seen acc.u.mulating here and there on a pedestal underneath a mounted specimen, know that dermestes are actively at work somewhere above.

Sometimes the larvae will even show themselves on the hair, which means a bad case.

If a perfect moth is seen flying in a case, or resting on a specimen, search at once for the larvae. The best way to do this is to go over a specimen with a rough brush, or a comb, to see if the hair pulls out at any point. If a tuft of hair gives way at its roots, and you see a bare spot underneath, it means moth larvae.

POISONING.--Let us take first the case of a mounted specimen which is known to be infested with the larvae of either _Dermestes_ or Tineids. It must be treated thoroughly all over with a powerful poison, not only to kill the insects already there, but to poison any larvae that may be hatched hereafter and seek to attack it.

If possible, remove the specimen from its pedestal, and beat out of it whatever dust it may contain. Procure a quant.i.ty of alcohol sufficient when diluted with fifty per cent of water to completely saturate the hair (or feathers) of the specimen, and dissolve in it some corrosive sublimate--about one ounce to every three pints of the liquid. The point to strive for in making up such a solution is to make it as strong with the corrosive sublimate as it can be without leaving on dark hair a gray (or white) deposit when the liquid has evaporated. In practice I always mix the liquid, and then test it with a tuft of black or brown hair. If the deposit left is quite apparent to the eye, a little more alcohol and water must be added. The principle of the process is simply this: The alcohol, being at once very penetrating and very volatile, and also capable of combining chemically with the corrosive sublimate, is used as a vehicle for the distribution of the poison. The poison is carried to the roots of the hair and left there as a deposit when the liquid evaporates. In Chapter XVIII.

the method of applying this solution is described. a.r.s.enic water, also described there, is _equally good_, and any intelligent person can make up either solution and apply it successfully without the slightest difficulty.

When the specimen has dried, the hair must be dressed by brushing and combing it. If the white poison shows on the hair, take a sponge, and with either hot water or alcohol sponge off the _surface_ of the hair, leaving all the unseen poison undisturbed. If your solution contains the proper amount of poison, and is thoroughly applied, I warrant that insects will never again touch that specimen, even though it should exist a thousand years.

It often happens that moths get into cases of birds, or mammals, or insects, which cannot be treated as above without damaging the specimens.

In such an event there are several poisons of a volatile character which give off fumes so deadly that no insect can live in them. The best for this purpose is naphthaline crystals, exposed in the cases in little bags made of musquito-netting, used in abundant quant.i.ty, and left in the cases, which must of course be kept closed as tightly as possible. In insect collections each box should have a little cone of crystals,[12] as a standing menace to all would-be marauders. Liquid or crystal bisulphide of carbon, exposed in saucers on the bottom of a tightly closed case will also kill whatever living insects may be found therein; but it does not destroy eggs, and by the time it has evaporated another generation of destroyers may have been born, hungrier than the first.

A half-ounce bag of naphthaline crystals will last about three months. Mr.

John B. Smith, who published in the "Proceedings of the Entomological Society of Washington," vol. i., No. 2, p. 113, a very interesting paper on "Museum Pests," found in treating some boxes of coleoptera that were infested with _TroG.o.derma_ that both bisulphide of carbon and naphthaline killed all larvae and imagoes, and held all the eggs in a dormant condition, even through the summer months, until the poison had all evaporated, when the eggs began to hatch.

At present naphthaline in the form of crystals has become the most popular of the various volatile poisons, and among ornithologists, mammalogists, and entomologists is very generally used. It prevents mould, destroys bacteria and schizomycetes; the salt is perfectly neutral, is not poisonous to man, and is cheap, costing only twenty-five cents per pound.

POISONING TEXTILE FABRICS AND SKIN CLOTHING.--Objects of this cla.s.s can not be put through any liquid poison, for the reason that some would be made hard and stiff, some would lose their colors, and all would come out in bad shape generally. To meet the exigencies of such cases one alternative is to poison the atmosphere of an air-tight case with some of the volatile poisons already mentioned, and the other is to treat each article with some powerful liquid poison, applied as a fine spray with an ordinary atomizer of gutta-percha, which can be purchased for from one to two dollars. The immense collections of the department of ethnology in the National Museum have necessitated a great amount of poisoning in both these ways, especially the latter, which has the merit of being permanent. In the "Smithsonian Report for 1887," vol. ii., pp. 549-558, Mr. Walter Hough has published a very complete, lucid, and valuable paper on "The Preservation of Museum Specimens from Insects, and the Effects of Dampness," which every zoological conservator should read and hold for ready reference.

In spraying large objects Mr. Hough uses either a Shaw & Geary No. 2 air-compressor (cost, $15) or a four-nozzle gutta-percha atomizer ($2.50), and the spray is from the following solution:

Saturated solution of a.r.s.enic acid and alcohol 1 pint.

Strong carbolic acid 25 drops.

Strychnine 20 grains.

Alcohol (strong) 1 quart.

Naphtha, crude or refined 1 pint.

For treating specimens of ordinary size with the concentrated fumes of bisulphide of carbon, the National Museum uses a galvanized sheet-iron tank 3 2 2 feet, which has around its upper edge a deep groove filled with water, into which the rim of the cover fits when the tank is closed. The centre of the cover contains an air-hole, which is also capable of being hermetically closed in the same way. This tank should be used in the open air, if possible, so that the fumes will not injure the health of the operator.

POISONING RUGS.--It has long been a problem how to poison a fur rug to protect it from insects, and yet to keep out of it the dry mineral poisons which would be injurious to the health of the little ones, the dog, and the cat, who are "tenants in common" of the bear-skin on the floor. Mr. F.S.

Webster has solved the difficulty by poisoning all his rugs on the inside with our old and valued friend, a.r.s.enical soap. It strikes into and through the skin, of course, and, contrary to previous expectations, it is by no means offensive, or even noticeable by odor in the finished rug.

FURS.--Even in Washington, the City of Moths, Mrs. Hornaday carried the family rugs and furs, and all woolen clothing, through eight summers, unscathed, by the liberal use of camphor gum alone. If the crumbled gum is sprinkled liberally into the folds of anything when it is being folded or rolled up, its protection against moths is a.s.sured.

INSECT POWDERS.--For the benefit of the American housewife I will mention the fact that for the complete annihilation of ants, roaches, water-bugs, and the like, there is nothing that I know of that is so far-reaching and so deadly as a powder produced in California called buhac, costing sixty cents per pound. The price is high, but the powder is well worth it--and this is an absolutely free advertis.e.m.e.nt.

THE EFFECT OF POISONS ON THE TAXIDERMIST.--a.r.s.enical soap is by all odds the safest poison that can possibly be used. It gives off no poisonous fumes whatsoever, its presence in the mouth, nose, or eyes is always detected instantly, and the worst that it ever does is to get into a cut or under the ends of the finger-nails of the careless taxidermist, and make a festering sore which is well in a few days--a purely local ill.

Dry a.r.s.enic is more injurious. It sometimes poisons the fingers of a careless operator, and if it is inhaled in the form of dust the effect may be serious. A few persons are very susceptible to the effects of dry a.r.s.enic, others are not. If the blood is in a healthy condition there is little to fear from it, except through gross carelessness. I have used, all told, probably more than a hundred and fifty pounds of a.r.s.enic in various forms, and never had an hour's illness in consequence, nor anything more serious than a sore finger.

Corrosive sublimate is much more powerful and more dangerous. It should never be used in the preparation of a skin before it is mounted; after mounting it may, with care, be used quite safely.

Strychnine is far too dangerous to be used by a taxidermist save in poisoning animals he wishes to secure as scientific specimens.

FOOTNOTE:

[12] Made and sold by Blake & Co., Philadelphia.

CHAPTER XLV.

USEFUL INFORMATION.

_Recipe for Making a.r.s.enical Soap._

White bar soap, soft rather than hard 2 pounds.

Powdered a.r.s.enic 2 "

Camphor 5 ounces.

Subcarbonate of potash 6 "

Alcohol 8 "

Directions: The soap should be the best quality of laundry soap, and of such composition that it can be reduced with water to any degree of thinness. Soap which becomes like jelly when melted will not answer, and should never be used.

Slice the soap and melt it in a small quant.i.ty of water over a slow fire, stirring sufficiently to prevent its burning. When melted add the potash, and stir in the powdered a.r.s.enic. Next add the camphor, which should be dissolved in the alcohol at the beginning of the operation. Stir the ma.s.s thoroughly, boil it down to the consistency of thick mola.s.ses, and pour it into an earthen or wooden jar to cool and harden. Stir it occasionally while cooling to prevent the a.r.s.enic from settling at the bottom. When cold it should be like lard or b.u.t.ter. For use, mix a small quant.i.ty with water until it resembles b.u.t.termilk, and apply with a common paint-brush.

The prices charged for the manufactured article by chemists who make a.r.s.enical soap to sell are out of all proportion to the cost and labor involved, and every taxidermist who uses much of it should by all means manufacture his own supply.

_Hendley's Enamel Varnish._--Take equal parts of ether and alcohol, mix them, and add one-third as much gun-cotton. To every gill of this mixture add six drops of olive-oil to give elasticity. It is a good plan to keep two bottles, one containing the varnish ready for use, and the other containing the proper mixture of ether, alcohol and olive oil, to use in thinning the varnish when it gets too thick. This is a very superior varnish being absolutely colorless, and of high gloss.

_The Wickersheimer Solution for the Preservation of Fleshy Objects Entire._--

Alum 500 grains.