KNIFE LORE   NUMBER 36    JULY 1991 NATIONAL KNIFE MAGAZINE

BERNARD LEVINE'S KNIFE LORE 

(c)1991 Bernard Levine, exclusive to the NKCA


DON'T LET 'EM BUG YOU

  Collectors of old straight razors know them best: the 
nasty little buggies that feed on horn handles.  Actually, 
it's not the bugs themselves that collectors know and hate.  
It's the ugly and discouraging damage that the insidious 
insects do to precious antiques.  It's the priceless old 
pressed horn handle that now looks like Swiss cheese.  It's 
the tortoise-shell handle that now looks like a tomato slice 
with the seeds removed.  
  And it's not just razor collectors who know and fear these 
depredations.  Indeed, it was a phone call from a distraught 
collector of mint antique pocketknives that prompted the 
present essay.  He had just discovered that every bright and 
shiny horn handled and tortoise-shell handled knife in his 
collection was as shot full of holes as the first duck to 
fly over the blind on opening day of waterfowl season.  
  Custom knifemakers, and those collectors who fancy their 
hand-made work, are not immune either, especially with the 
current popularity of sheep horn for custom knife handles.  
Indeed, the severely damaged sheephorn shown in this photo 
came from the store-room of a very unhappy knifemaker.  Note 
how the outside of the horn appears intact, but that the 
inside has been almost entirely eaten away.  

PICTURE 1 
CAPTION: Heavily munched Bighorn sheep horn

  So what causes this unsightly and costly destruction, and 
what can you do to prevent it?  You might also wonder what 
can be done to repair the damage, but I will save you the 
trouble of worrying about that question: nothing can be done 
to un-eat devoured horn.  On a custom knife, you might be 
able to get gnawed handles replaced.  On an antique piece 
you are pretty much out of luck.  


THEM DERN DERMESTIDS

  I had long been aware that something eats horn handles, 
but I had never actually observed the culprits, nor 
witnessed their depredations in progress.  I had even made 
up a name for the villains, just as small children make up 
names for their imaginary playmates, or as unscrupulous 
knife dealers make up histories for their fantasy knives.  
  I called the villains "horn weevils," even though I knew 
that weevils could not really be to blame.  You see, weevils 
are sucking insects, not chewing insects, and they simply 
could not eat horn, no matter how hungry they were, even if 
they put Worcestershire sauce on it.  However, "horn weevil" 
sounds like "boll weevil," and everybody knows what a pest 
boll weevils can be.  My imaginary "horn weevils" must be 
just as bad.  
  But now, having received a cry for help from the 
aforementioned pocketknife collector, the one whose handles 
were being devoured, I figured that it was time to unmask 
the real villains.  Was it cosmic rays?  Was it mutant 
nematodes?  Was it spontaneous combustion?  Whom should I 
ask?  
  Well, the obvious choice was to call my contacts at the 
Smithsonian.  If anybody has had to deal with this problem, 
it's got to be museum people.  
  Sure enough, the curatorial staff at the National Museum 
of American History knew just what I was talking about.  
They referred me to museum conservationist Beth Richwine, 
who has made a special study of insect depredations on 
museum collections.  She gave me the straight skinny.  The 
villains are the Dermestidae, particularly the genera 
Anthrenus and Attagenus, better known as the carpet beetles.  
  Carpet beetles got their common name back when nylon was 
just a gleam in the eye of DuPont scientists, and most 
carpets were still made out of wool.  Carpet beetles took 
shelter in wool carpets, and happily ate the wool.  They do 
far more damage to woolen goods than do clothes moths.  
  Wool, as you know, is simply a form of animal hair.  It's 
soft and slick and fluffy, but still it's just hair.  True 
horn (such as sheep horn, cattle horn, buffalo horn, goat 
horn, antelope horn, even rhinoceros horn -- all those horns 
which are never shed) also are animal hair, just hairs that 
happen to grow all together, rather than in individual 
strands.  And while tortoise shell isn't hair, it is close 
enough down at the biochemical level to satisfy a Dermestid.  
In fact, some Dermestids invade insect collections and munch 
on the dried and mounted bugs.  Others eat bird feathers or 
spider webs.  If it's dried out animal protein, there's a 
Dermestid somewhere who will be happy to eat it.  
  As far as carpet beetles are concerned, if a wool rug is a 
like a salad bar, with the goodies all spread out so that 
they can pick and choose, then a chunk of horn or turtle 
shell is like trail mix or a granola bar, with everything 
nutritious compressed into one convenient package.  And if 
you are looking for quick calories with minimal effort, do 
you go for the tossed salad or for the trail mix?  The trail 
mix, of course.  Ditto the Dermestids.  


PARENTS AND CHILDREN

  To be strictly correct, it's not the carpet beetles that 
eat horn, or even wool.  Adult Dermestid beetles are gaily 
flitting flower elves who eat nothing but pollen.  It's 
their nasty little larvae, their little baby grubs, who prey 
upon our precious proteinacious possessions.  
  Adult carpet beetles are tiny.  The largest variety is 
barely a quarter inch long, and most are considerably 
smaller.  One common variety is basic black in color, but 
most of them are camouflage blotched in yellows, browns, 
grays, and black.  Some are even fuzzy.  They are much 
smaller than the familiar ladybird beetles, and they are 
neither as brightly colored nor as regularly marked.  

PICTURE 2 a,b,c,d
CAPTION: Adult Dermestid beetles, vastly enlarged

  Adult Dermestid beetles crawl and fly from flower to 
flower, gorging on pollen, and spreading enough of it around 
to help the host plants to reproduce.  When the female 
beetles are ready to lay their eggs, they search out warm 
dark locations rich in stable animal protein in which to 
nest.  Such an environment provides the optimum combination 
of shelter and nourishment for their tiny hungry offspring.  
  These sorts of nesting environments are sometimes few and 
far between in nature.  Most typical are sun-dried carcasses 
and skulls picked clean of flesh by vultures, hyenas, 
carrion beetles, maggots, and such.  Others are abandoned 
animal dens and bird nests.  No doubt many Dermestid mamas 
never find a suitable such location at the right time -- at 
least not out of doors.  
  However, human habitations are full of warm cozy nooks and 
corners, many of them lined or filled with wool or down or 
fur, and so made to order for a broody Dermestid.  After 
all, that is our favored nesting environment, too, despite 
our inability to digest the organic insulation.  And since 
Dermestid beetles are far too small to ring doorbells, they 
long ago trained human beings to carry pretty cut flowers 
into their homes, thus giving the tiny camouflaged adult 
Dermestids a free ride into our homes -- and right to their 
happy camping grounds.  
  Once indoors, mama Dermestid can pick and choose amongst 
an unlimited variety of bed-and-breakfast sites for her 
descendants.  Inside the left horn of Uncle Ralph's trophy 
Bighorn ram?  Deep in the horsehair stuffing of Aunt 
Clothilde's heirloom couch?  Safe in the warp of Grandma 
Sophie's $18,000 oriental carpet?  Cradled in the soft and 
secret recesses of Cousin Sue's cashmere sweater drawer?  
Hidden in the box with Grampa Mortimer's horn-handled 
straight razors?  Snug in the felt-lined knife rolls where 
you thought your precious horn-handled folders would be 
secure?  
  Aha!  
  So mama Dermestid, by sight and smell and touch, finds her 
way to a perfect nesting spot, lays her eggs, then flies 
away to hang out in retirement flowers until she dies.  In 
due course her eggs hatch, and out come the voracious little 
larvae.  

PICTURE 3 a,b
CAPTION: Dermestid larvae, also vastly enlarged

  Carpet beetle larvae start out minuscule, but they eat and 
eat and grow and grow, until finally they get to be tiny.  
Even full size they are well under a quarter inch long.  And 
what they eat and eat to grow and grow on is animal protein.  
They like it dry and stable, and preferably rich in keratin.  
  Flesh is not for them.  Neither is bone, which is why they 
don't bother antler -- unless it is velvet antler, in which 
case they eat the velvet, along with some of the outermost 
surface of the antler, leaving distinctive squiggly white 
trails.  Their meat and potatoes is horn and hair -- not too 
appetizing to most other organisms, but as rich as mother's 
milk to them.  
  These little larvae are fuzzy, like their favored 
environment.  They are decorated all over with tufts of 
bristles, which, depending on the species, range from pale 
blond to jet black.  Perhaps this serves as camouflage.  
  Like many grubs and caterpillars, Dermestid larvae are 
deeply segmented.  You are not likely to see them in action, 
but they leave behind split-open shed skins which they 
outgrow and cast in plain sight, sort of as a Dermestid 
"Kilroy was here."  Make that "killjoy was here."  These 
light brown cast skins display the critters' deep 
segmentation.  

PICTURE 4
CAPTION: Half a dozen of the scores of cast skins of 
Dermestid larvae left inside the badly tunneled Bighorn 
sheep horn shown above.  


FIRST AID

  So now that we know the culprit, what might be the cure?  
Alas, as in most of mortality's afflictions, there is no 
absolute cure.  However, there are a few tricks and habits 
that can improve your odds, and these are probably the best 
that we can hope for.  The basic drill is prevention, and 
here are some of the things you can do in that direction.  
  First and foremost, do not keep horn or tortoise shell 
handled cutlery in or near cloth or cloth-lined containers.  
To do so would be like trying to scare away winos by hanging 
up a "Rescue Mission" sign.  Cloth lined rolls and cloth 
pouches are great for carrying knives to shows, and for 
storing knives with other types of handles, but do not leave 
your horn handles in them for extended periods of time.  
Even if the cloth is not wool, mama Dermestid won't care, as 
long as there is nice tasty horn wrapped up in it for her 
babies to eat.  
 So what should you keep these sorts of knives in?  That's a 
tough question.  If you seal them up in plastic or glass, 
the bugs won't eat their handles, but condensation and rust 
will eventually eat their blades and springs.  
  A good choice might be snap-top plastic medicine bottles.  
Your pharmacist might be willing to sell you some in various 
sizes.  They are ultraviolet resistant, and their lids are 
air and bug tight.  Because they are quick to open, they 
will encourage you to open each one regularly, to air out, 
inspect, and clean the knife stored inside.  
  Before storing any knife, it should be carefully wiped 
with a soft cloth to remove fingerprints, then lightly wiped 
with a clean cloth dosed with a few drops of USP food-grade 
mineral oil, or Japanese sword oil.  [This camellia-scented 
mineral oil is available from the Japan Woodworker, Alameda, 
California, (415)521-1810; also from Garret-Wade in New York 
(800)221-2942.]  Inspect and wipe stored knives at least 
once a month.  
  Should you exclude flowers from your house?  No, that 
won't solve the problem.  Flowers are Dermestids' favorite 
vehicle, but these tiny insects can also ride inside on your 
clothing, on your pets, even on your groceries.  Some of 
them are small enough to crawl in right through window 
screens.  Do examine the blooms and rinse off the stems and 
leaves of cut flowers, however, and don't keep flowers in 
the same room as your knives, or near other valuable horn, 
wool, fur, or hair items.  
  For serious Dermestid infestation of large items such as 
sofas or rugs, professional fumigation might be required.  
This would be overkill for pocketknives, of course, but 
knifemakers who store a large inventory of horn might look 
into it.  One maker of my acquaintance, after suffering 
serious loss of stored horn to Dermestids, now dusts his 
handle material inventory with the insecticide Carbaryl 
(also called "Sevin") and then stores the treated horn in 
plastic bags.  I do not know how effective this is, nor how 
potentially hazardous the Sevin might be.  
  Traditional taxidermists have long been aware of the 
Dermestid problem.  When mounting a horned animal, or its 
head, they would remove the horns from the skull.  Then they 
would pack the horns' hollow innards with a special plaster 
richly laced with arsenic.  Then they would reattach the 
horns.  
  In theory, anyway, the arsenic in the plaster would kill 
any Dermestids which hatched inside the horns.  Since 
arsenic is an elemental metal, it would remain active in the 
mount indefinitely.  Sevin, by contrast, is an organic 
compound, which breaks down over time.  
  Incidentally, if you attempt to salvage the horns from an 
old taxidermic mount, be aware that there is probably enough 
arsenic in that white filler inside the horns to kill you, 
or at least to make you very sick, if you saw it or grind 
it, and breathe or handle the dust.  You should treat this 
filler as hazardous toxic waste, and wrap it up and discard 
it as local law requires.  If you must saw through it, wear 
a respirator and protective clothing, and clean everything 
thoroughly afterwards.  
  Ms. Richwine at the Smithsonian says that she avoids the 
use of pesticides within the museum, although large badly 
infested objects (such as carriages with horsehair filled 
cushions) are sent out to be fumigated.  She has 
experimented with freezing small horn objects to kill 
Dermestid eggs and larvae, but she is not certain of the 
long-term effect this treatment might have on the horn 
itself.  She does not recommend freezing steel-bladed 
objects, and neither do I.  
  If you do find signs of insect infestation in your knife 
collection, or other items, you might want to seek 
professional advice.  Your first stop might be the 
entomology department of your's state's Land Grant 
agricultural college or state university.  The folks there 
can probably identify just what's eating your goodies, and 
make suggestions for dealing with the problem.  

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