the preservation of museum specimens from insects and

THE PRESERVATION MUSEUM SPECIMENS FROM

INSECTS

AND THE EFFECTS OF DAMPNESS.

By

Walter

Hough,A. M.

The

preservation of

museum

specimensis of no lessimportance than their acquisition. Periodicallythe attack of

some new

insect, or the infestingof

some new

^material,isbroughtto thenotice ofcurators,

and

hitherto

many

specimens

have

been destroyed which it

would

be

now

impossibleto replace. In a great

museum

the

abundance

ofthe mate- rial will not permit its frequent examination, so that all specimens should be thoroughly poisonedbefore they get out ofsight. There are

many

things

which

one

would

not thinkit necessary to poison, yetall

should be, for nearly all organic structures have peculiar enemies in the insect world.

As

instances,

woodwork,

basketry, textiles, botan- ical specimens, etc., should be poisoned with corrosive sublimate, asit

coagulates the albuminoid principles in vegetation

and

thereby pre- ventsdecayas well as the attacks of insects.

The

ravages of

moths have

been experienced from remote times,

and

thoughthe preservation of materialsfromthe attacks of these

and

other insectshas been repeatedly attempted, all efforts, itseems,

have

so far beenineffectual.

Most

of the chemical substances suggested are too poisonous to be used on articles brought in contact with the person, asin every-day wear. Happily this is

no

objection here, for with ordi- naryprecautions thespecimens senttothe

Museum

can betreated with the strongest poisons, the

main

difficulty being to avoid

damaging

the material in theirapplication.

Firstinrankof destructiveness are the moths,of

which

four species

have

been observed at active

work

in the

Museum.

These are Tinea flavifrontella Linn., the

common,

or clothes,moth; T. tapetzellaLinn.,or carpet

moth;

T. pellionella Linn.,or fur moth,

and

T. granellaLinn., or grain moth. These Tineids arenight-flying insects, though the little fluttering «_millers^w are often seen flying indarkenedroomsintheday- time. Their natural habitatisindry animal

and

fibrousvegetable sub- stances,

and

sometimes on the fur of living animals; in houses they infestwoolens,furs, grain, etc.,

and

the destructioncaused

by

thelarvae iswell

known. They

beginto flyabout activelyin

May.

I

have

ob- served

them

in

warm rooms

as early as March,

and have

found the

larvae, allthrough the winter. In the stage in

which

this insect does 549

550

its destructivework,itisa

plump

whitecaterpillarprovidedwith strong mandibles

and

sixteen legs. It nips the fiber, beginning as soon as hatched from _{the Qgg,}

and

buildsa casewhich is enlarged as the insect grows. These insects are

known

to travel in search of other quarters;

they areveryhard to kill,extreme cold doesnot affect them,

and many

ofthedomestic preventives,such ascamphor,tobacco, etc.,entirelyfail todestroy them.

All articlessubject toinjury from these

moths

^should beoften exam- ined

and

shaken, especially in spring

and

early

summer,

to dislodge the eggs.

Another

very serious pest is the "buffalo

bug"

(Anthrenus lepidus Linn.),

and

itsrelativethe "carpet

bug"

(A. variusFabr.).

The

adult

isa smallround sluggish beetle,brown,with whiteorvariegated scales on the

wing

covers.

The

larva? are short,

plump worms

with numer- ous stiff,

brown

hairs. This insect is on the increase; its ravages

seem

to

have

attracted the notice of the public,

and much was

written about

ita few years ago, in1882

and

1883. Likethe tinea larva, thebuffalo-

bug

larva cuts leather, woolen, or fur,

and

builds an incoherent case from thefragments.

These

insects multiply veryrapidly,

and

are also unaffected

by

ordinary insectpreventives.

The

larvaeof the "basket beetle" (Sitodrepapanicea Linn.) are small worm-like creatures with six minute feet.

They

are furnished with strong cutting-jaws

by means

ofwhich they eat their

way

intobasketry

and

old wood, or similar substances, boringlittle holes as round as if

made

with a fine drill.

The

adult insect is a little, sluggish,

brown

beetle which simulates death on being disturbed.

Another

insect, the subject of a letterto Science,

May

28, 1886,

and

therecalled

"A New Museum

Pest," is the "silverfish"(Lepismadomes-

tied).

The

adultisashining fish-shapedinsect,wingless,but veryquick

in its

movements.

Itprefers starch for food,

and

attacks everything that contains that substance,such as labels pasted or sizedwith starch or mucilage, cotton or linen laundered goods, etc. This insect is ex- tremely obnoxious to librarians, being attracted

by

thepasteused in binding books.

Other

insectsare oftenintroducedinto the

Museum

on specimens

and by

othermeans, but these are ofless consequence,as theydonot breed there

and

are usuallynot harmful.

It hasbeen thought well to introduce here a paper by Mr.

John

B.

Smith, assistant curator of entomologyin the

Museum,

relating tothe care of insect collections. It

was

publishedin the Proceedings of the EntomologicalSociety of

Washington,*

underthetitle

"Some

Observa- tions on

Museum

Pests."

Oneof the duties ofa person in chargeof a largecollectionof insects is keeping out museumpests,as the various species that feedonthe driedinsectsare generically called. In a large collection, like that of the National Museum, no inconsiderable

'Vol.^i, No. 2, p. 113.

timeisrequiredforthat purpose,asittakesat leasttwo weekstogothroughallthe boxescarefully.

It has beeu the fashion to recommend as a certain preventive tight boxes, and quarantiningallspecimensbeforeputting intothe collection, andundoubtedlythis isanexcellent precaution, saving much future labor. It is,however,byno means the certainremedyithasbeen claimed to be. Theboxesandcabinetsinuseinthe

Museumare asperfect,as far assafetyisconcerned, as it is possible to getthem at present,yetwithal constant care is required. Psocidwwill find theirwayintothe tightestboxes, and though they do little damage ordinarily,yetin a collectionof Tineidcv,orminuteDiptera, theycandoconsiderabledamage. ForthesepestsIhave found naphthalinea perfectremedy.

A

singlehalf-ounceconeisa perfect protection, andlastsaboutthreemonthsordinarily.

Tineidlarva?are rather rarelyfound in the collections on the larger moths, and arenotalwayseasilydiscovered, sincetheymake no dust, as do the Anthreni. On oneoccasionIfoundthatone pairofwingsof a C. regalis suddenlycollapsedwith- outapparentcause. Closeexaminationshoweda Tineidlarva thathadbeenfeeding onthe dense, longvestiture, making galleries in all directions in suchawaythat

whenItookhold ofone endof thegallery,thevestiture of theunderside cameoff inlargesheets, leaving thewings almost clean, the veins broken here and there,

which producedthecollarnse. They rarelyburrowinto the specimen,never in

my

experience. Ptinidcearesometimesfound,butareexceedinglyrareinourcollection.

One box linedwith corn pithwas riddled bythem,and a very few specimens were attacked. Byalloddsthemost dangerous enemiesarethelarvaeof the Dermestidw, whicharepestspureandsimple. TheprincipalenemyinourcollectionisAnthrenus varius, thoughTrogodermaisnotuncommon.

My

experiencewiththeseis, that in theuniformlyhigh temperaturepreserved in the laboratorythey breed all the year around,and have nodefinite broods; afew larvaeappearatalltimes,thoughduringthesummer,whenthe beetlescomeinfromthe grounds,and fromother partsoftheMuseum,exposed specimensareattackedatmore regularintervals. Theruleistokeep naphthalineinallboxesatalltimes, but, like all rules,it isnotalwayspossibletoadherestrictlytoit. Theboxesnot so protected are usuallyfirstattacked. In a cabinet not quite tightIconed anumberofdrawers andleftthe others unprotected. Inthecourseofthesummertheunprotected drawers nearlyall became infested, while as a rule the otherswere^free. Thenaphthaline seemstoactasarepellaut. Ihavefound,however,thatitdoesnotannoythelarvae toanyvery great extent, andMr.Luggerhasshownmea naphthaline coneinahol- low^ofwhicha larvahadpupated. Ihavereason tobelieve,however,thatitdoesre- tard thedevelopmentofyounglarvae.

A

largenumberof boxes, nearlyone hundred, were received from North Carolina, containing a collection, principally Coleop- tera. Theywere overhauled and found to be prettygenerallyinfested with Trogo- derma, thisbeingtheonlyspecies found. No Anthrenus larvaewerenoticed. Bisul- phideofcarbonwasfreely used, andnaphthalineconeswereplacedinallthe boxes.

For awhiletheboxeswere frequentlyexaminedandnolarvaedeveloped. Through- out thesummertheboxes wereexaminedatintervalsandremainedfree. With the approachof coldweather they wereleftfor a longer period andthe cones nearlyall evaporated. In December thiswas noticed,and the boxes were againoverhauled, anditwasfoundthataverygeneraldevelopment of larvae had begun, allof them Trogoderma, and noneof them morethan 2to3millimeters in length,mostof them apparentlyjust hatched. The entire collectionwas scrutinized,and an occasional Anthrenus larvawasfound, butnoother Trogoderma,evenin themost exposedboxes.

Iconcludefromthisthat thecollectionwhenreceivedwasinfested, andthat there weree{gseverywhere readytodevelop; somehad beguntodevelop,andthesewere destroyedbythe use of bisulphide of carbon,whichalsoservedtocheckthedevelop- mentoftheeggs. Theboxeswerequitelarge,andtwolargeconeswere putineach_; they werealsoquitesecure,andtheatmosphereinthem wasfullyimpregnated with

552 REPORT OF NATIONAL MUSEUM,

^1887.

theodorof naphthaline. Throughoutthesummer,whenunder ordinary circumstances theywouldhavedeveloped, theegg3remained dormant, butafterthenaphthalinehad evaporatedcompletely, developmentbegan. Imight addhere thatTrogodermaisan exceedinglyrare pestin

New

York,andnotcommoninWashington;farthersouthit

seems to replace Anthrenus. For allthese pests bisulphide ofcarbon isasovereign remedy, exceptwhentheyareburrowinginlargeColeopteraorLepidoptera. Ihave repeatedlysoakedlarge Bombycidswith chloroformorbisulphide, andaweeklater foundthemstillinfested. Iworkedforamonthoversomelarge Lucanids(Procule- jus),andfinallyseparated the partssothatIcouldfillthe body cavitywith chloro- form. Inonecase, thatwas somewhat exposedandcontainedold material of little value,I found a specimen destroyed by Microgaster, a rare parasite for Anthrenus.

How

theygot atthisboxisdifficultto explain, sinceitwastightenoughtoprevent theentranceof theinsect.

Ihavenoticed also thatboxesonthelowertierofshelves aremuchmoreliableto attackthanthoseon uppertiers, andthisleadsmetobelievethat theparentbeetle willdepositeggsoutsideof theboxesoronthefloorofthecases,andtheyounglarva) willworktheirwayintothe smallest crevices. Itseemsdifficulttoaccountforiso- latedlarva3inboxescontainingonlyoldinsects.

FinallyI find the dangerof infection comparativelygreaterat Washington than in

New

York, principallybecausethe

warm

season beginsearlierandlastslonger,in- creasingthechancesofinfection. Ifind,too,that the onlyrealchanceof safetycon- sistsinconstantexamination,tight boxes,andafreeuseofchloroformorbisulphide of carbon.

As to naphthaline, I consider thatit isa goodgeneral preventive. I knowthat itkeeps outPsocidsandants. Itenhances the tendencyto greaseandto verdigris,

andin tight boxesit seems to exercisea relaxing tendency,causing thewings to droop.

There are several classesof substances tobepoisoned, in

which

the colors, fabric, orcharacter ofmaterial,

and

therefore thekindofpoison

and

the strength ofsolution,areimportantfactors.

For

instance,goods not fast

dyed

(especially cotton), or

which

are

dyed

with colors that contain solutions, will start; also fabrics or substances which

may

be corroded or hardened, or otherwise injured, as feathers, fur, dressed deer-skin, etc.

Too

strong a solution

may

alsocause a deposit onfur, etc.,witha dulling effect.

As

atest forthis,a black feather shouldbe dippedinthesolution,if it isofcorrosivesublimateorarsenic inalcohol.

If thesolution betoo strong, itwill produce a whitecoating

when

dry.

Any

solution shouldexertits actionin

two

ways,first torepelthe adult insect,

and

second, todestroythe hatched larva.

Pungent

odors are noxious to

moths and

the higher orders of insects, but this is hardly true in the case of thebeetles to which

we ^have

before alluded.

The pungency

of odor can not be

made

to last long, so that the poisoning qualityis of prime importance.

The

substances used for solutionsare deadly poisons,

and

no one

who

has not

had

^{experience in handling}

them had

better undertake to apply them. Corrosive sublimate will attack the finger-nails

and

the skin. It is also volatile. Arsenic is prejudicial to the health; thedust, it is said, produces catarrh, both gastric

and

nasal, thoughthis has not been confirmed

by my

observa- tion.

Before poisoning, all objects should betreated withbenzine,

by

put-

ting

them

in a close

box

or vessel,

and

pouring* thebenzine in, leaving

them

tightlyclosed thereinfor severaldays. This operation destroys

any

larvae or eggs.

They

should then be

hung up

until the benzine evaporates beforeproceedingwith the poisoningsolutions. Bisulphide of carbon is

more

volatile

and more

quicklyeffective thanbenzine,

and may

beused,ifpreferred. Thereis reason to believethat bothkill the eggs

—

^{quicklyif thefluid}

^comes

^{incontact with th«,m}

^and

^{less rapidly}

iftheyare directly affected only

by

thefumesin the vapor. Great care

must

be takennot to allowfireof

any

kind to

come

incontact with the vaporof bisulphide of carbon. There are several reasons

why

benzine

is preferable,

and

the latter is sure to beeffective

when

followed by the arsenic-naphtha solution.

The

solution found

most

satisfactory for poisoning nearly every kindofspecimensisas follows:

Saturated solution of arsenic acidand alcohol 1pint.

Strongcarbolicacid 25 drops.

Strychnine 20grains.

.Alcohol (strong) 1 quart.

Naphtha, crudeorrefined 1pint.

The

use of strychnineisnot absolutely necessary;butitisavery

good

agent

and

adds

much

tothe value of the solution.

Other

solutions

and

poisonswillbenoticedbelow. It willbe found advisable toapplysolu- tions in theform of sprayto delicate objects,such asfeathers orspeci-

mens

ofsimilarcharacter. In thistreatment an atomizer

may

be used.

Some

small specimens

may

be dipped

and

allowed to drain,

and

the solution

may

be appliedwith abrush toa large class ofobjects,taking caretosaturateevery part.

The

specimens can then be

hung up

todry or laid

away

as they are.

They

should be kept freefromdust,which

is exceedinglyinjurious tothem.

As

soon as poisoned, they ought, if

intended for exhibition, to be

mounted

in dust-tight cases, or carefully stowed

away

in close-fitting drawers or boxes. In unit or costume boxesasmallpacketofnaphthaline

may

beconcealed behindthespeci- mens,

and

the junction of thelidshould be

made

dust-proof

by

pasting

on

strips ofpaper with paste containing arsenic orcorrosive sublimate.

Some

specimens presentproblems thatdonotfall under anyrule

and have

tobe^left to

judgment and

experiment.

As

an instancein point,

we

mention afine deer-skin robe collected

by

Mr. Turner, beautifully tawed, with the hair on,

and ornamented

with a

medium

whichwill not stand wetting. Itis obvious that no solution can be used in this case, since alcohol orwaterwill harden the buck-skin

and

destroy the decor- ation. Satisfactory results

might

be obtained

by

judicious spraying, butthere

would

be doubt astothecompleteness of the poisoning. It

would

bebetterto rub into the kid surface a

powder made

of precipi- tated chalk

and

whitearsenic.

The

fur sideshouldthenbewellrubbed, care being taken toallow the

powder

topenetrate intotherootsofthe hair.

By

all

means

protect the

hands

with gloves.

Powdered

soap

would

also be a

good medium

for the arsenic. Great care should be

554 REPORT OF NATIONAL MUSEUM,

1887.

takenin applying this poison

and

in handlinga specimen poisonedin thisway.

Such

specimens should be at'once closed

up

tightly

and

put on exhibition.

Corrosive sublimate has been

much

used for poisoning

and

isa valu- able agent. Several specimens in the

Museum, which

were poisoned years agowith this substance,wereso filledwithit thatthey are dusty.

They

are

made

of fur-skin,

and

are stiff

and

unpresentable^forexhibi-

tion. Ido not

know what was

the condition of the articles

wheu

they wereacquired; theyare,however,undeniablymoth-proof. I

have

found

numerous

adult

moths

destroyedinthe act oflaying theireggs.

A

care- fuluse of corrosivesublimateisveryeffective, if it isnot broughtincon- tactwithskins,asitcoagulatesalbumen. Itisalso volatile,

and

Dr.G.

H. Beyer, U.S.

Navy,

has proposed totake advantage of thisproperty in preventingthe

growth

offungi on materia-medica specimensin jars.

One

objection to corrosive sublimate is that it crystallizes out very easily; this

might

be obviated

by

adding a little

naphtha

tothe alco- holic solution.

Naphthalineis used by Mr.J. B.Smith, of the

Museum, and by

other entomologists, to preserveinsect collections from Acari,Psoci, Dermes-

tes,Anthreni,

and

other

museum

pests.* It destroys the

two

former, butonlytends torepel the others. It also acts as an antiseptic, de- stroyingschizomycetes,moulds,bacteria, etc.

The

saltisperfectlyneu- tral, is not poisonous to

man, and

is cheap. It is customary in this department to put a small packetorcones in cases containing

mounted

costumes.

Vaseline

may

be called perfect grease, since itdoes not

become

ran- cid or corrosive. It is especially useful toprotect iron

and

steelfrom

rust,

and

no doubt

would

preserve

woodwork

from extraneous attack.

Itis alsogood tosoften leather

which

has

become

hard. In the case of clubs, spears,

and

implements of hard wood, likethose of Polynesia, a finepolish

may

be obtained

by

using vaseline. Iregard vaseline asa good vehicle in

which

to apply white arsenic to skins, asis done with arsenicsoap. It penetratesverywell,especiallyifthinned alittlewith naphtha. Vaselineis also usedon book-backs to soften them, to pre- vent mould,

and

tokeep insects away.

A

few recipes

germane

to this subject,

and which may

be useful in other departments ofthe

Museum,

areappended:

Mr.

Hornaday

has used arsenical soap prepared in the following

manner:

Whitesoap 2pounds.

Powderedwhitearsenic 2 do.

Camphor

~

5 ounces.

Subcarbonateofpotash 6 do.

Alcohol 8 do.

Seep. 555.

PRESERVATION OF MUSEUM

SPECIMENS.

555

Slice the soap,melt it,

add

the potash,stirin thearsenic,

and add

the

camphor

previously dissolvedinthealcohol. Stir,

when

cooling, to pre- vent the arsenic from sinking tothe bottom.

For

use,

mix

a small quantity with water until it resembles buttermilk,

and

apply with a

common

paint-brush. This is a mechanical mixture. Mr.

Hornaday

has obtained resultsof thehighest order from itsuse.

The

following

isbelieved tobe a

more

correct chemical combination

Whitesoap 1ounce.

Arseniate ofpotash 2 do.

Water 6drachms.

Camphor 2 do.

Strychnine(ad lib.) 15 grains.

The

following ingredients

make an

effectivepreservative

powder

Whitearsenic 1pound.

Burntalum 1 do.

Powdered oakhark 2 do.

Camphor -£ do.

This should be

powdered

well, sifted

and

keptin well-stopperedbot- tles. It should be applied to the

wet

surface of skin

and

rubbed in well.

The hands

should beprotected with gloves. I

have

nevertried thispreparation.

The

following solution has been prepared

by

Wickersheimerforthe preservation of objects in the natural state:

Alum 500grains.

Salt 125 do.

Saltpeter 60 do.

Potash 300 do.

Arsenic trioxide (whitearsenic) 100 do.

Dissolve in 1 quart ofboilingwater. Cool

and

filter,

and

for 1 quart of thesolution

add

4 quarts of glycerine

and

1 quartof alcohol. Either soaktheobjects in thesolution, orinject

them

withit. Thissolution is said todo verywell exceptin tropical climates.

For

botanical specimens thisissaid tobean excellent preservative

One

ounceof corrosive sublimate to 1 quart of alcohol, diluted 50 percent.

The

best planisto dipthespecimens

and

thencarefullydry them.

The

poison can also bepainted on witha camel's-hair brush.

For

the preservation of entomological specimens, the strongestsolu- tion used should be corrosive sublimate in alcohol, 1 to 100,

and

the weakest0.1to 100. (See remarks onnaphthaline, ante.)

For

insects onplants, the following solutionsare

recommended

First solution.

Salt 2| pounds.

Saltpeter 4 ounces.

Water 1 gallon.

Filter.

Secondsolution.

Firstsolution 1 quart.

Arseniate ofpotash 2 ounces.

Water ! 1 gallon.

556 REPORT OF NATIONAL MUSEUM,

1887.

.<>•-

A

^{cheaper solution can be}

made by

taking

Whitearsenic : i pound.

Salsoda 4ounces.

Water 1gallon.

Boiltill a solution is made.

Take

1 quartto 40 gallons of water.

These solutions

have

been found

by

the

Department

of Agriculture to

be veryusefulindestroying the scale-bug

and

theredspider,so harmful to plants.

The

following

method

is

employed by

furriers inthe treatmentoffur skinsforthepurpose of rendering

them

pliable:

The

skin is steeped

and

scouredin a bathofalum,bran,

and

salt, inorder to

remove

greas- iness; thenin abathof soap

and

soda, to

remove

the oilfrom the fur.

When

thoroughly

washed and

driedit isfoundthatthepelthas

become tawed

or kidleather.

To

soften

and

cleanse buck-skin or chamois leather, rub plenty of castile soap ^intothe skin

and

soak for

two

hours ina

weak

solution of salsodain

warm

water

and

rubwelluntilquiteclean. Afterwardsrinse ina

weak

solution ofsalsoda

and

soapⁱⁿwater; afterrinsing,Wringit

dry in acoarse towel,

and when

^fullydrybeatit until soft

and

smooth.

For

domestic purposesthe following preventives

from moth

ravages aresuggested: Dissolvein200 parts of alcohol 2 parts ofsalicylic acid

and

2 parts of thymol;

perfume

with oil oflemon. This is a neutral solution

and

will notinjurecolorsortexture,

and

has apleasant odor, butisrather expensive.

A good

preparation to sprinkle

among

^furs being

packed away

in a close

box

or drawer,isnaphthaline

and

mentholorthymol,inproportion of 1ounceof theformer to20 grains ofeitherof thelatter,

rubbed

to- gether.

The

odomvilldisappear from thefurs orgoods afterthey

have

beenaired forashorttime.

Even

if

moths

arepresent

and

arehatched, theywillnotfeed

when

closelyshut

up

intheodorof this mixture,

and

in this respectitisfarsuperiortocamphor.

Thymol

aloneisverygood.

Naphthaline is

now on

the

market

in a very convenient shape called

"

moth

marbles,"

and seems

tobe goinginto general use.

Inthe following list of apparatus only those things

have

been

men-

tioned that

have been

found necessary orvery useful in the operations at the National

Museum.

Doubtless at other places,

where

such a rangeof subjects for poisoning is not presented,

some

of the articles canbe dispensed with

:

Gutta-percha atomizer,which

may bought

foronedollar.

The

bottle can beeasily wiredto a handleforconvenience. (Fig. _1.)

I'ig. 1. Gutta-perchaatomizer.

Galvanized sheet-iroivtank(Fig. 2) used for subjecting specimens to bisulphide of carbon.

The

lid

and

air-holecap

on

the lid both fitinto

557

aslot(Fig. 2a) that is tobefilled with waterto preventescape of gas.

The

tank should besetoutin theopen airifpossible.

The

sizeof the tank usedhereis 3by2

by

2feet,

and

ithas handles onthe ends

and

on thelid. (Fig. _2.)

Fig.2a.Showingadjustmentoflidof tank. Fig.2.Galvanizedsheet-iron tank.

Shaw ^{and Geary}

No. 2 air compressor (cost $15),

and

four-nozzle gutta-percha atomizer, cost $2.50. These are found necessary only

when much

^sprayingis tobe done.

Stock solution jar, jarfor

mixed

solution,benzine jar or jug, gradu- ate,1 pint; glass funnel,3 paint brushes,not too large; several stone- ware jarswith ^closely fitting lids for smallerspecimens.

With

good- sized jars, or even a closely-joined box, the galvanized tank

may

be dispensed with, especially

when

benzineis to be used.

The

poison tags should not be large.

They

are convenientfor show- ing whether specimens are poisoned ornot,

and

when,

and

are some- times agoodtestwhether theyarewell poisoned.

They may

beprinted with death's-head

and word

"poisoned," with space for date

and mu- seum

number.

The

long established "

Museum

standard" cases are provided with beadjand groove (Figs.3

and

4) which effectuallyexclude dust

and

in- sects, the

two

worst foesof

museum

collections. Inputting

up

perish-

y [ ^j

Fig.3. Section acrossbackof door. Fig.4. Sectionacrossjunctionof door.

able specimenspermanentlyinthe glazed

Museum

unit boxes,etc.,the backsare

made

of tin,

and

to

guard

against the minute,insinuating, newly-hatched

moth

larva, the junction of the lid with the sides is

pasted overwith strips of paper or muslin with glue, poisoned with corrosivesublimate orarsenic. This, with naphthalineconesinside, is

the highest triumphof the preservation of

museum

specimens.

558 REPORT OF NATIONAL MUSEUM,

1887.

Inthe following table are given the approximateprices of chemicals

which have

been referredto in thispaper:

Alcohol, 95per ceut $2.50 pergallon.

Arsenicacid, Merck's 40 perpound.

Arseniate of pot ash do.

Arsenic,white 10 do.

Benzine 15 pergallon.

Bisulphide ofcarbon .25 perpound.

Burntalum 10 do.

Camphor 25 do.

Carbolicacid, Calvert'ssolution 60 do.

Chloroform 75 do.

Corrosivesublimate (mercuricchloride) 90 do.

Ether 85 do.

Glycerine 30 do.

Menthol 50 per ounce.

Naphtha pergallon.

Naphthalinecrystals 25 per pound.

Naphthalinecones 1.25 per100.

Naphthaline"mothmarbles" 10 per box.

Oakbark,powdered, ortannin 10-.25 perpound.

Oiloflemon 20 per ounce.

Salicylicacid 2.25 per pound.

Saltpeter 35 do.

Salsoda 05 do.

Strychnine 20 per £-ounce.

Subcarbouateofpotash 25 per pound.

Thymol - 60 per ounce.

Vaseline,Cheeseborough's 50 perpound.