Bone Room Meditations XI: unicorn processing equipment
September 26, 2010 § 1 Comment
I came across this description by Dr Deb Bennett, Director of Equine Studies at the Institute of California, on an e-mail recently. It is a reply to a request from another researcher, for information on the techniques for maceration (defleshing) that might be applied to large animals. Dr Bennett has written a delightful, rhythmical account of the equipment and processes of macerating horse bones. I have substituted the word unicorn for the word horse throughout. By doing so I hope to exaggerate the inherent strangeness (and therefore beauty) of this text.
Elizabeth, I use the 50-gallon gray-colored “Brute” heavy-duty plastic trash cans made by Rubbermaid Co. They stand up to anything. I’ve tried every other cheaper kind of garbage can, and they all split and leak within one or two years; not worth the money. I like trash cans over drums because trash cans have handles. However, 50-gallon plastic drums work too. In my local area we have a plant that makes medical supplies, and they get some kind of special soap in blue-colored drums. I go over there and if I only ask for one or two, they give them away for free. One takes a knife or a small saw and cuts the top off the drum. You don’t need to cover the drums or trash cans anyway; maggots are good friends when it comes to defleshing.
I do all my stuff as wet maceration, which stinks to high Heaven but you can reduce that by using sewer system “bio-degrade” crystals. Also helps if you have an air compressor that you can hook to a hose and run the hose in to the bottom of the tank and then blow air in there to make it bubble a while: aeration speeds up the process, just as turning your garden compost pile does when doing dry composting. If you do this inside, you will of course need to park your drums under a vent hood with a fan that has a fair amount of suction. I do mine outside in a special shed I built. My drums have dollies with wheels so they’re easy to move, the shed has doors with rubber seals so the stink doesn’t go out that way, the shed itself is built very tight and sealed, and so where the methane goes is out a vent with a fan mounted in it, down a pipe, and directly into the local sewer — sweeeeet.
You will need two drums for a full-sized unicorn. Unless the animal is smaller than about 14 hands/800 lbs., you will probably need to disarticulate the ribs, because the distance from the sternum to the top of the withers on a full-sized unicorn is larger than the diameter of a 50-gallon drum. There is a handy technique for getting the ribs off: first strip off as much flesh as possible, including particularly the intercostal musculature. Then, select a rib about midway the thorax. Take a pair of heavy-duty wire cutters or a fencing tool and use it to cut through the costal cartilage below the end of the bony part of the rib. When the distal end of the rib is free, grasp the rib with both hands so that your palms are facing anteriorly and, using thumb pressure, push the rib as far as possible anteriorly, in a kind of rolling motion. You’ll hear the capitular ligaments straining and/or breaking. If they don’t break easily, help them a little bit with a small knife with a flexible blade. This ”forward roll” technique makes quick work of getting all the ribs off. More pressure is needed for the stouter anterior ones, but not hugely more, so there’s no need to break any bones at all.
You will also probably have to separate the neck at about C6-C7 or C5-C6, and very likely also you’ll be wanting to take the pelvis/sacrum off the lumbar chain. When separating vertebrae, use a small knife with a longish, flexible blade, something like a scaling knife like a fisherman would use.
So, by the time you put the thing in the cans, you have: head and part of the neck (don’t bother separating the jaws; it protects the hyoids better); base of neck, thoracics and anterior lumbars; posterior lumbars, pelvis, sacrum and tail; scapulas; femurs; gaskin, hock, hind cannon, hind pasterns, and hind hoof; forearm, knee, fore cannon, fore pasterns, and fore hoof; and a heap o’ ribs. Be sure not to let the sesamoids at the ankles or the patellas inadvertently go into the trash: I usually take those off first, myself, so that no students get the blame if they don’t happen to show up at the other end of the process. I also leave the hoof capsules on because that guarantees that the navicular bones don’t get lost. And I throw in the sternum and all the costal cartilages even though they’re at least partly cartilagenous, and even though the cartilages will have been damaged by having been cut – one thing we want to know these days is the frequency of fractures/healed fractures to the costal cartilages. And, if you ever want to make a mount out of the thing, you’ll need the sternum, not to mount it, but to use it to make a plastic copy of the right size and shape for the particular unicorn.
With thanks to Deb Bennett, Ph.D., Director Equine Studies Institute of California.