4" T\ Division of Ag'ric o Itural Sciences UNIVERSITY OF CALIFORNIA Xh;;*f) ANALYZING FUR DAMAGE WITH A MICROSCOPE ROY J. PENCE ? CALIFORNIA AGRICULTURAL Experiment Station Extension Service CIRCULAR 541 Cutaway and cross-section of an animal fiber (guard hair) showing internal structure. The cortex is made up of millions of cortical cells. The medulla is partially hollow. (Modified from Wool as an Apparel Fiber, by G. E. Hopkins. N.Y.-To- ronto: Rinehart & Co., Inc., 1953.) -T ur damage is often difficult to diagnose with the naked eye — especially after the fur has been cleaned or brushed, and the loose, visible evidence has been removed. This circular describes and illustrates with photos cer- tain unmistakable characteristics of various kinds of damage, including that caused by insects, as seen under the microscope. Fur-damaging insects are also described and shown, and a section is included on the care and protection of furs. The Author : Roy J. Pence is Specialist, Department of Agricultural Sciences, University of Cali- fornia, Los Angeles. October, 1966 Section of cover photo showing natural mink fur severely damaged by carpet beetle larvae feeding. Guard hairs have been cropped down to undercoat in places. Given time, all fur would be eaten down to skin. [2] Analyzing Fur Damage y with a Microscope Why the microscope' Two to four select animal skins that are finished to make up a small fur neckpiece, such as a boa or a twist, can be priced upwards of four figures. However, even commonplace pelage of lesser worth re- quires expert dressing, cutting, and fin- ishing. This processing places a note- worthy price on all furs, regardless of origin. When a fur is damaged, it is often important that the cause be firmly estab- lished. If the owner feels he is not to blame, he may wish to seek evidence to be used against someone else. This can lead to litigation, and sometimes experts must be called to examine the damage and to testify as to its nature and cause. However, such experts on fur damage are not always at hand, nor, for that matter, is literature on the subject. The following information and photo- graphs based on microscopic examination of fur damage caused by insects, fire, cuts, rents, and the like, has been pre- pared to provide means to base diagnoses on facts rather than circumstantial evi- dence. Research indicates that certain kinds of damage, regardless of appear- ance to the naked eye, reveal unmistak- ably characteristic clues when subjected to the microscope. Such causes, then, can be ruled out, and unidentifiable damage can be attributed only to insufficient knowledge of the fur's history. No matter what a fur costs, it deserves good care and protection. A section is also included on the prevention of insect dam- age by means of correct storage methods, repellents and insecticides. Insects not always to blame Bare areas on a fur usually direct suspi- cion to feeding insects. It is common knowledge that clothes moths and carpet beetles will seriously damage material made of animal fibers, and that, as a rule, insects are not observed until after dam- age occurs. However, "snap" diagnosis of insect damage can be made only if their living or dead bodies, fecal pellets, cast skins, or other obvious signs, such as fiber par- ticles, are apparent. If "insect"-damaged fur is submitted for examination after it has been brushed, cleaned or manipulated in any manner, and such evidence is re- moved, a microscope is needed to deter- mine accurately the reason for damage. Indentations or fissures can be made by fire, or chemical or mechanical means; and bald areas can be caused by various forms of wear. Other disfigurements superficially re- semble injury caused by insect feeding. However, regardless of how any "clean" or apparently undamaged area appears to the unaided eye, there will almost always remain some unmistakable clues for the microscope to reveal. Fire A lighted cigarette or match, or any open flame, will scorch, sear or burn animal [3] Fig. 1. Profile of natural mink fur, showing the skin, soft, downy undercoat, and stiffer but conspicuous, guard hairs extending beyond. fibers. Fur will not normally burst into flame but may flare briefly and melt into pockets of blackened fiber ends. The ob- vious discoloration and characteristic odor of burnt hair quickly identify recent fire damage, but old burns are more di- fficult to detect. Once burn damage has been subjected to brushings or other cleanings, evidence to the naked eye dis- appears — until examined under the mi- croscope or a powerful hand lens. To make the diagnosis, tweeze out or cut a damaged guard hair of the greatest length and diameter from the fur at the skin line. Guard hair is composed of the longer fibers of fur which tend to protect and conceal the shorter fibers, or under- coat (see figure 1). Then cut an identi- cal guard hair from an undamaged por- tion of fur, and touch its tip with a lighted match. When the fiber has burned down to a corresponding length of the original damaged fiber, clean the burned end of blackened ash. If the profiles and ends of both fibers are observed to be similar under the microscope, then fire can be held responsible for damage to the origi- nal hair. At least three characteristics peculiar to fire-damaged fur can be seen (figures 2 and 3) . 1. Immediately beneath any burned, dark-pigmented fiber end a "'bleached" area will be found resulting from pigment loss due to heat just under the kindling point of fur. Conversely, this area on a natural white fiber that has been burned will be a shade darker than it is on an unburned fiber. 2. The most conspicuous sign of burn appears when looking directly through the microscope at the cleaned, upright end of the fiber. This is an inside view of the same "whitish" zone (cortex) ob- served when the fiber tip is held in pro- file position. The up-ended view also shows that the cortex is perceptibly de- pressed — leaving a thin, elevated, and somewhat translucent wall of cuticle. The cortex is more combustible than the cuti- cle, and it melts down beneath the cuti- cle's protective wall. 3. Another important clue is the swell- ing of the cortex due to heat. Internal pressures cause the burnt fiber tip to be- [4] Figs. 2 and 3. Left (fig. 2): fire damage to dyed squirrel fiber; ash still intact. Note characteristically swollen cortex and slight bleaching. Next four photos (fig. 3): fire damage to natural mink guard hairs showing various degrees of cleaning following burn. Left, thoroughly cleaned fiber with only hollow, flared tip remaining. Center (two), cleaned fiLjrs with ash removed — cuticle projects beyond tip. Right, brush-cleaned fiber with part of ash still intact. come moderately flared or bell-shaped. Damage characteristic of singeing and hot grease burns can be seen in figures 4 and 5. Rents, ruptures, and cuts Most dry animal fiber can be extended or stretched up to 30 per cent of its length before a break occurs. (Wet wool fiber may stretch to approximately 60 per cent.) If, however, fur fibers are steadily pulled, or even yanked from the skin, they usually lift free from the follicle without breaking. A crimped or violent pull, however, may cause fiber to fracture before being freed, and result in broken ends. The cortex of animal fibers is made up of millions of small spindles, called cor- tical cells. (See drawing on page 2.) If a fiber is fractured, splintered ends of the cortical cells and fragments of cuticle, as a rule, will project beyond the point of rupture. Microscopic examination of se- verely ruptured fiber ends reveals various Fig. 4. Typical singed tip of guard hair of natural mink. Singeing occurs when fur is passed close to an exposed light bulb of high voltage, wattage, over a burning candle, or any open flame. Prolonged exposure to hot sunlight, or any heat source may cause fiber tips to singe. [5] • ' '■'"■■" ■ l^&^^^i;^'-^^^:?'' 1 Fig. 5. Hot grease burn damage to guard hairs of natural mink. Upper fiber is undamaged. Two lower fibers are swollen to almost twice their natural sizes. Hot grease or oil also causes straight fibers to curve during process of swelling. If hot grease penetrates to skin, fibers loosen and fall free, leaving * a bald area. Partially burned fibers surrounding the area will show varying degrees of swelling. Fig. 6 (left). Violent rupture of natural beaver fiber. Note stretched and irregular fragments of cortex and cuticle extending beyond break. Fig. 7 (right). Typical razor cuts of guard hairs from natural mink. ■ Note slivers of cuticle extending beyond ends at point where blade slides upward on completion of cut. 4#* 'Ik: I m I § [6] gradations of splintering when viewed in profile. This distinctive symptom of rup- ture damage can be noted in figure 6. The resilience or elastic properties of animal fibers resist the straightforward thrust of most cutting blades, but sep- arate readily if the instrument is handled in a slashing manner. The sharpest surgi- cal scalpel or razor blade will cut through the cuticle of a hair fiber, enter the cor- tex and medulla, then continue through to the inner wall of the cuticle until the point of exit is reached. Because over 90 per cent of the fiber's rigidity is now lost, the partially severed fiber will "hinge" backward and strip free of the remaining cuticle, leaving a thin, bark-like fragment of this material extending at the rear and above the severed surface. Appearing clean and rounded to the unaided eye, the microscope reveals this protruding frag- ment as proof of fur damage caused by blade cuts (figure 7). Hair fibers cut by scissors are marked with faint but unmistakable signs. A scis- sors-cut pinches or flattens the "spongy" cortical cells of a fur fiber to the point of separation (figure 8). Under the mi- croscope it appears to be cut clean, but tapered. This asymmetry is caused by the extreme stretch exerted by one blade holding the fiber, while the other pinches through. When viewed in profile and slowly rotated, or examined head-on in an upright position, the offset taper be- comes evident. Wear Signs of wear to fur are most easily recog- nized if past events and time are taken into consideration. Evidence of gradual wear can be found at the elbows and col- lar of a fur coat (figure 9). Abnormal wear can occur on any area that is ex- posed to accelerated friction, (i.e., when fur is caught between two hard surfaces) . Fig. 8. Left, typical scissors cut of dyed squirrel fiber. Slight flare is caused by pinch and stretch of fiber during cut. Right, asymmetrical bevel of horse hair caused by greater stretch on one side during pinch and shearing action. Fig. 9. Worn guard hair of natural mink. The resiliency of long, unbroken fibers normally resists wear; however, constant abrasion may break fibers, leaving shorter, less resilient shafts that wear down to rounded, shattered tips. [7 Catching fur caught in the moving parts of a door latch will result in instant wear. The circular motion of a thumb pressed on a fur surface will cause the shorter undercoat fibers to twist and mat, and some guard hairs will break or bend into them. Continuous and violent wear re- duces both content and identity of hair and causes eventual patches of bare skin. Normal wear of fur may be difficult to detect, even under the microscope. Some remaining fiber tips may be found smoothly worn, but most are completely absent. The very flexibility of any long, single hair prevents it from "wearing out" when intensively rubbed; usually it will fall out or break before it is reduced to stubble. The microscope is useful in detecting such damage to fur only when it is severe enough to materially alter fiber construc- tion or color. Normal wear or other subtle forms of damage, such as that caused by strong light, weathering of fiber tips, or chemical exposure, may hamper detection unless it can be accurately associated with the history of the fur. Such circumstan- tial evidence may help, but microscopic examination is also necessary to rule out clues unrelated to wear. Chemical damage Animal hair fiber is keratinous (nitrog- enous substance forming a large part of hair, nails, claws, and horn) . It is difficult to destroy; strong acids will not break it down, and most strong bases will do no more than soften or possibly bleach it. Hair so treated may become brittle in time and finally break, but it is difficult to trace the cause. Some chemicals may cause hair to "fall out," leaving little visual evidence behind to prove why. An exception occurs with common household III III W -1 Fig. 10. Bleached area on fur of Russian dyed squirrel caused by spillage of strong peroxide. Solution was strong enough to destroy skin beneath, but only bleached the fibers. Application of undiluted house- hold bleach (with its sodium hypochlorite content) produced a similar appearance, but utlimately it caused fibers to drop out and skin to be destroyed. [8] 2 ^jte;.' ■:p%^, f :v:- \ ■ Fig. 11. Damage to fiber of Russian dyed squirrel caused by spillage of undiluted household bleach. Light areas are bleached and destroyed to a point where the fiber can easily be pulled apart. bleaches and liquid chlorines. The so- bleach and break down animal fiber (see dium hypochlorite in these products will figures 10 and 11) . Clues to insect-caused damage Fiber-feeding insects need the vitamins and amino acids found in association with their scavenger diet. "Clean" fur lacks these supplements and must be contami- nated with a certain amount of soilage, food spillage, and related nutrient sources before a normal insect life cycle can oc- cur. Contamination is inevitable; it is caused by perspiration, body oils, or, for that matter, even air-borne micro-organ- isms, that synthesize certain elements of nutrition. In short, "clean" fur is possible only through sterilization; for once ex- posed to air, or even brief handling, it soon becomes sufficiently contaminated to provide an acceptable diet for fiber-feed- ing insects. This does not imply that "clean" fur is immune to hungry insects, but it is less "appetizing." Contaminants are rarely absent in one form or another in some measure on every fur. Feeding scars One unmistakable clue to insect-damaged fur remains when all evidence visible to the naked eye is absent — mandibular scars on the individual fiber. Mandibles of fiber-feeding insects are designed by nature to cut cleanly through animal hair leaving a concave scar (fig- ure 12). Each mandible half is rounded at the tip with a slight pocket formed on the inside. This figuration forms a sharp knife edge which meets the opposing mandible half in much the same manner as the jaws of a pair of nail cutters or surgical bone-cutters. Size of mandibular scars may vary, but their configuration remains the same. Small scars found in association with larger ones indicate that younger larvae fed in the same area as older forms. Very young larvae may inflict minor damage usually indicated by five to twenty mi- nute indentations observed along the shank of a single fiber (figure 13) . Fully developed larvae sever a small, intact hair with a single bite. Whatever the mandible size, individual feeding scars are definite and vary only in dimension and arrangement. (See figure 14 for mi- croscopic view of mandible scars en- graved on a plastic surface.) A fiber that has been severed with a single bite, or one requiring perhaps two or three bites to sever, is easily iden- tified by its concaved end or "scalloped" appearance (figure 15) . Hair stubble appearing slightly above or flush with the surface of a "naked" patch of skin is another clue to concen- trated insect damage. Insect larvae can eat fiber right down to the epidermal sur- face, but rarely beneath. Peltage which [9] Fig. 12. Mandibular scars and areas of concentrated feeding by half-grown carpet beetle larvae on guard hairs of natural mink. has been completely denuded by insect feeding might give the appearance of a closely shaved face (figure 16), but at all times fiber stubble can be detected with almost any visual aid. Also, the in- evitable mandibular scars always appear on the close-cropped fiber ends. Other evidence The microscope might also detect insect larval hairs which are characteristic of each species among the fur fibers (fig- ure 17) . Without the microscope Careful observation with the unaided eye may reveal fecal pellets (figure 18) and two bites of a fully developed carpet beetle larva. V Note the concave shape of the severed end caused V by rounded mandibles. [10] Fig. 13. Linear feeding of young (second and third instar) carpet beetle larvae on different ani- mal fibers. Larger fiber on left shows progressive mandibular scars resulting from single "meal." First of two smaller fibers on right was fed upon in linear manner and then severed by localized feeding in one area. Remaining fiber on far right was fed upon by a third instar larva capable of deeper bites. Fig. 14. Mandibular scars of carpet beetle larvae engraved on plastic surface to show pattern of random feeding. Compare with scars on mink nail (fig. 16). Fig. 16. Carpet beetle larvae injury to fur, toe, and nail on the paw of a neck-piece of natural mink. Feeding scars on remaining fiber, and com- plete shearing of fur down to the toe, are evident. ^ *> * ■ fei> ***& ^8s» "^^l*^ Fig. 17. Characteristic segmented shaft and ornate, spear-pointed tip of a single hair from a carpet beetle larva found lodged in damaged fur. (Magnified approx. X 372.) cast skins (figure 19) in undisturbed in- nearly always the same color as fibers sect-infested fur. Shaking may dislodge fed upon. most of them, but a few usually sift deep Larvae and insects themselves, of beneath damaged areas, with some cling- course, can sometimes be seen on a fur. ing to the sides of fibers. The pellets are Photos of some of these are included in the following section. Fig. 18. Fecal pellets of carpet beetle larvae always found in association with cast skins in undisturbed insect-damaged fur or wool. (Magnified approx. X 30.) r '■• 9 i Fig. 19. Cast larvae skins are important clues to diagnosing damage. Upper, furniture carpet beetle; lower, black carpet beetle. Feeding insects con- stantly shed their skins, which closely resemble the living insects. (Magnified approx. X 7V2.) Fig. 20. Adult and larvae of webbing clothes moth. Note characteristic matted fecal pellets and webbing which are always associated with this species. $<#- "** „ * m [13] Species of fur-damaging insects Many insects of minor importance to this study are capable of damaging fur by "sampling" or shredding fiber rather than by actual feeding. Such insects in- clude silverfish, cockroaches, crickets, earwigs, and certain moth larvae, which sever fibers for use in constructing co- coons. Damage by these and other insects is incidental, and attention here is fo- cused on important Lepidoptera (moths) and Coleoptera (beetles), which are known to feed on fur and other keratinous substances as a source of food. Lepidoptera Webbing clothes moth. Tineola bisselliella (Hummel) Adult. (Figure 20). Approximately % inch long, wings uniformly golden buff-colored, top of head covered with bristling reddish hairs. Moths are light- shy and weak fliers. Females capable of laying upward to 200 eggs, with 40 to 50 being average. Larva (matured). Approximately V2 inch long, naked and cream-colored. Spins webs over feeding areas and pro- duces silken tunnels or tubes for protec- tive purposes; webbing characterized by copious amounts of fecal pellets and fiber particles scattered throughout. Excre- ment is usually same color as fur upon which larvae have fed. Life history. One month to four years, depending upon dietary and en- vironmental circumstances. Life cycle normally completed in 65 to 90 days. Case-making clothes moth, Tinea pellionella (Linn.) Not as common as the webbing clothes moth, but capable of serious damage to animal hair. Adult. Slightly smaller than webbing clothes moth, brown wings rather than golden buff. Three dark spots on each fore-wing of newly emerged adults. Spots frequently rubbed off with age. Larva. Unlike webbing cloth moth larva (which is a free-webbing species) the casemaker envelopes its body in a « silken tube, and remains inside during the entire larval period. The case will be dragged behind as new feeding areas are < sought. Often the protective case will be composed of various colored fibers inter- woven with silk, creating a multi-colored effect. The case is vital to the larva which soon perishes once it is removed. Life history. Similar to that of the webbing clothes moth. Coleoptera Black carpet beetle, Attagenus piceus (Olivier) This species is of little importance in California; however, infrequent reports are received of its occurrence in granaries or, temporarily, on woolens or furs which have just arrived from the eastern and middle states, where it has gained the reputation of being the most destructive of all carpet beetles. Adult. Two and eight-tenths to 5 mil- u limeters long and dark brown to black in color. May be found outdoors feeding on pollen, but enters homes during the spring and early summer. Females lay from 42 to 114 eggs and generally die a few days after oviposition. Larva. Typically carrot-shaped, 7 to 8 millimeters long, somewhat shiny brown to black. Long tail bristles re- semble fine paint brush. Exist under a wide range of environmental conditions, but grow more rapidly at a temperature of 80°F and a relative humidity of 65 per cent. Food consists of a number of proteinaceous substances, including dead animal matter, fur, horn, and cereals, as well as processed food. Life history. If food and environment are not suitable, larvae may require more than 639 days to develop, and undergo as many as 20 molts before pupation. Under [14] Fig. 21. Adults and larvae of two common species of carpet beetles that attack fur. Left, furniture carpet beetle; right, varied carpet beetle. favorable conditions larvae may reach pupation in 258 days and complete a life cycle in little less than a year. Furniture carpet beetle, Anthrenus flavipes Le Conte This cosmopolitan species (figure 21, left) is extremely important in California. Like the varied carpet beetle, this species feeds on a variety of plant and animal matter. It appears to thrive in a slightly drier environment in California than the varied carpet beetle, and is often found infesting woolens, carpeting, and fur in [15] the upper stories of high buildings. Adult. Slightly larger and more rounded than the varied carpet beetle, a definite cleft at the posterior. Mottled yellow, white and black coloring is also more conspicuous. Female may lay up to 96 eggs in separate batches. Larva. Torpedo-shaped with head re- gion wider than posterior. The darker colored larva can run swiftly from place to place, unlike the varied carpet beetle larva. Extremely destructive to carpeting, upholstered furniture, brushes and furs; will even feed upon certain cellulose ma- terials such as linens, cotton, and syn- thetics when associated with suitable con- taminant. Life history. Under favorable con- ditions, the life cycle may be completed in as little as 10 to 13 weeks. At room temperature, the time from egg to adult varies from 149 to 422 days, depending upon nature and availability of food supply. Varied carpet beetle, Anthrenus verbasci (Linn.) A cosmopolitan species of considerable importance in California (figure 21, right) , the varied carpet beetle thrives in nature on carcasses of dead animals, dead insects, birds' nests, etc., in addition to a wide variety of plant products. Adults are pollen-feeders and enter homes during the spring and early summer, where they readily deposit their eggs on any suitable food supply. Adult. Two to 3 millimeters long, slightly oval-shaped, and mottled with white, brownish, and yellowish scales. Larva. Mature larva is 4 to 5 milli- meters long, body marked with a series of light and dark brown transverse stripes. Three dense tufts of bristles occur on either side of the posterior, which lie flat when undisturbed. When molested, the larva extends these tufts outward in a "fan-shaped" display of small but con- spicuous puffs. Larva is slightly wedge- 1 shaped with posterior broader than the head (which is the reverse of the torpedo- shaped furniture carpet beetle larva) . i Food consists of woolens, furs, stuffed animals, feathers, horn, silk, fish meal, cereals, and almost any processed plant or animal food. Typical of all carpet beetle infestations, copious amounts of cast skins and fecal pellets are scattered throughout the feeding areas. Life history. Food supply and envi- ronmental circumstances dictate length of life cycle. This varies from slightly less r than one year to as long as a year and one- half. The number of molts varies from five to 16, and averages seven or eight , instars. Common carpet beetle, Anthrenus scrophulariae (Linn.) The common carpet beetle, although widespread throughout the world, is of little or no importance in California. The beetle was a serious pest in Buffalo, New York, during the 1870's, at which time it was given the name "Buffalo bug," and so it remains to this day. i- Adult. About 3 millimeters long, oval- shaped, blackish, with a varied pattern of whitish and orange scales on the back. A scalloped band of orange-red scales ap- pears down the middle of the dorsum. Adults are pollen-feeders. Larva. Mature larva is reddish-brown with numerous black or brown hairs ex- tending outward over the entire body. Like the furniture carpet beetle, this species is active in movement, and runs rather than crawls. In addition to feeding freely on carpeting, this insect attacks t furs, feathers, leather, brushes, silks, and mounted museum specimens, as well as pressed plants. Life history. At room temperature the average period of development from egg to adult is 94.5 days, with a range of 89 to 108 days. [16 How to prevent insect infestations Storage A fur, professionally stored under refrig- eration, fumigation, or a combination of both, should not be subject to insect dam- age. However, home storage in the far reaches of a closet or deep in a drawer provides an ideal environment for insects which not only feed, but reproduce pro- digiously. Such damage can easily be prevented, i however, by periodically reversing the insects' environment. If darkened, unmo- lested food supply is optimum for an in- sect's needs, then a lighted and disturbed food supply discourages an infestation. Furs should be exposed monthly to bright light and shaken thoroughly. As a rule, it is the forgotten fur or woolen that suf- fers insect damage. Frequent warm airings of fur away from the direct beating rays of sunlight may actually kill an existing insect in- festation. Care must be taken, however, to avoid any outside airings during the spring months. This is the flight period for a number of "wild" carpet beetle species, and a time when gravid females are seeking suitable food upon which to lay their eggs. A fur coat or woolen piece hanging on the line provides a ready target for egg-laying carpet beetles. Such ► egg-infested material brought into the home and stored for the summer could be found seriously damaged by the time it is brought out in the fall. Repellents (moth-proofing materials) A number of commonly used "moth- proofing materials," such as moth balls or crystals are, in reality, repellents (al- though in some cases insects are actually killed). The materials mentioned here will be broadly considered to be repel- v lents. Most insect repellents protect the fur against insect attack. Rarely are they [ capable of killing an insect infestation already established when used in the nor- mal manner. The success of any material depends upon amounts used. Excessive quantities in a tightly sealed area might in some cases serve as a fumigant and destroy mature larvae of fiber-feeding in- sects; but the strong, unpleasant odor of most of them is hardly worth a question- able control. Cedar chips, camphor, naphthalene, paradichlorobenzene, etc., have been used for years as "fumigants" in confined areas where furs and woolens are stored. Old-fashioned moth balls continue to serve a purpose in repelling insects. Some preparations are scented to mask a dis- agreeable odor. Care should be taken to prevent possi- ble stains caused by some volatile insect repellents. Paradichlorobenzene in partic- ular will leave a noticeable discoloration if allowed to melt in contact with surfaces containing invisible impurities. For this reason, raw crystals of this or other evaporable repellents should not be scat- tered over a fur or woolen placed in a storage chest or drawer. They should be placed in tight but porous containers near but not in direct contact with stored items. At best, cedar chests and closets only aid in protecting furs against potential insect infestations, and should never be depended upon to destroy insects already in existence. Insecticides True insecticidal moth-proofing materials are often used successfully on wool, but never on expensive furs. Indeed, insecti- cides need not be considered if any one of the previously mentioned recommen- dations is followed. Dust insecticides are not only unsightly but tend to absorb beneficial oils from natural animal fibers, leaving them brittle 17] and subject to breakage. Also they are effective only as long as they remain on the fur, and must be replenished pe- riodically to maintain efficiency. Sprays that kill insects usually contain either water, oil, or an alcohol base, and must be applied with great force to pene- trate hair mat and reach the skin, where insects are hiding. Many sprays leave a stain, in addition to altering the natural luster of fur. Unless fur has been dye vat- treated with an insecticide, it fails to re- main fast. This means it must be sprayed on regularly due to its limited lasting properties, if insect-proofing is to be maintained. Frequent warm airing out of doors and brushing and shaking is far more prefer- able to prevent infestation than the use of insecticides. ACKNOWLEDGMENTS Fur samples for this study were donated by George Benioff furriers, Oakland, Cali- fornia, who also offered constructive comments on the section concerning fur care. 10m-9,'66(G5257)P.A.V. KNOWLEDGE GAINED BY RESEARCH CAN HELP CONSERVE CALIFORNIA'S WILDLAND RESOURCES CALIFORNIA WILDLANDS... • 65 million acres of mountains, foothills, canyons, rivers, lakes, and sea coasts. • a giant "farm" for timber and forage. • a vital source of California's water supply. • an "outdoor playground" for millions of vacationers. THE THREAT: the onslaught of... population growth. urban and industrial expansion. • increasing demand for water, lumber, forage. • wildfires. • insects and plant and animal diseases. • waste. THE SOLUTION: coordinated research on using wildland resources to realize their full potential . . . • present rate of timber growth could be doubled. • usefulness of timber cut could be doubled by new products made from current waste. • forage production for livestock and game could be tripled. '-.'• • watersheds could be made to yield more usable water and cause fewer floods. VNy>J. tens f m j||jons of dollars lost to fire, insects, diseases could be saved. •• timber, forage, and recreation uses need not exclude each other. THE WILDLAND RESEARCH CENTER at the University of California was established to help conserve California wildland resources through research. It operates within the University's state-wide Agricultural Experiment Station, with administrative headquarters on the Berkeley Campus. THE CENTER... • coordinates and supports research in more than a dozen fields. • integrates studies of complex wildland problems. • strengthens cooperation between University and other research workers. • promotes the exchange of information between research workers and wildland managers and policy makers. • collects and disseminates scientific data on wildland studies. TO KNOW IS TO LIVE IN ABUNDANCE