Fun With Fluids: Days Three & Four

Yesterday was a slightly slower day than intended, but I did manage to finish preserving both the frog and lizard and get them into their final solution of 80% IMS, and then mounted the frog on his backplate. Which was an odd experience – I took textiles GCSE, but it did not prepare me for threading a frog! With a very large, curved needle and monofilament thread. He did look good when he was finished, despite still being a little crunchy – the rehydration process didn’t seem to have much effect on his appearance.

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At the end of the day I managed to prep the jar and glass backplate for the harbour crabs, so that I had everything ready this morning to crack on with mounting them. Tying them to the backplate was a fairly quick job, but then came the harder task of reattaching the stray claws and legs with glass needles. I first had to decide which crab which limb belonged to, and then exactly where each limb should go. It took quite a long time, but I got there in the end!

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There are still a few more limbs missing, but they weren’t in the jar with the specimens so must have been lost long ago. Once in their nice new jar, though, the crabs looked much happier.

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Sadly, by the time I’d finished mounting the crabs, and had sealed the jars of my finished specimens, I didn’t have time to finish the lizard. I had the jar prepped, and all ten holes drilled in the backplate, but I didn’t have time to mount it. One of our conservators has offered to finish it for me tomorrow, and I left her with the worst diagram of a lizard ever drawn to show her how I had planned to pose the lizard, which I hope will help her to sew him to the backplate in the right position. He’ll probably end up looking much better than if I’d done it!

Poor little Varanus waits patiently for a new jar

Poor little Varanus waits patiently for a new jar

There has been a huge amount to take in this week, as there are so many different processes involved in restoring dried-out specimens, and I’m now quite exchausted. But I am really pleased with the results of my specimens, and I’ve learned a whole host of new skills that I feel confident I could put to good use in the future if someone put a shrivelled specimen in front of me.

If you have wet-preserved specimens in your collection that you don’t know what to do with, or don’t think you can rescue, I’d highly recommend going on Simon’s fluid preservation course – I was amazed at how well all of the specimens we worked on this week came out. They all started as dry, sad-looking husks, and by the end of the week most of them looked ready to go on display!

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OLYMPUS DIGITAL CAMERAChameleon, octopus (named Little Chulhu) and sea slug, prepared by Gina

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Fun With Fluids: Day Two

Today began with us checking our specimens in their baths of Decon-90. My harbour crabs were declared done and ready for fixation, but the tree frog was still rather stiff and unresponsive, so he went back on the hotplate to cook a little longer.

‘Fixing’ specimens involves bathing them in a fixative, in this case formalin (a dilute solution of formaldehyde dissolved in water), which stabilises tissues by binding to amines in protein, making them less soluble and mobile. Most specimens also need to be injected with formalin, to ensure that it penetrates the whole body and the internal organs don’t start to degrade. My crabs did not need injecting, as the formalin could get inside the carapace fairly easily to reach the tissues.

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Here you can just about see the glass microscope slides being used to force my still floaty crabs beneath the surface of the formalin to make sure that it penetrates evenly.

While our specimens were busy fixing, we went for our morning’s lectures, which included information on the various jar sealants that have historically been used and which one is likely to come across in a museum collection, mounting pelagic specimens using monofilament wire and glass backing plates, and also information on dealing with fluid-preserved botanical specimens.

Next it was back to the lab, where my frog was finally supple enough to be fixed in formalin, and my crabs were ready for the next stage. Once fixed, specimens are usually then transferred into alcohol, which acts as a preservative and prevents them decaying over time. A solution of 70 – 80% Industrial Methylated Spirits (IMS) is used for this. But with specimens that have dried out completely in their jars (as mine had), they can’t be put straight into 80% IMS, as this would damage them. Instead, they need to be stepped up in gradual stages to 80%, starting with a low alcohol concentration.

But before my critters could go into their alcohol, they had to be treated for the air inside them that was causing them to float. This was done in a dessication chamber attached to a vacuum pump, which pulls the air out of the chamber, and removes air bubbles from the body cavity of the specimen.

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Unfortunately, while quite a lot of air did come out of my specimens, they failed to sink totally, even after several treatments in the vacuum. As the frog will be mounted on a glass backing plate anyway, this isn’t too important.

While waiting for my specimens to work their way up the alcohol ladder, I also attempted to make a lid for the frog’s jar by cutting a circular piece of glass from a sheet…after three failed attempts, I resorted to a ready-cut lid! Which is cheating, but I did at least get the principle of how it should work, and why mine went wrong. I also drilled a hole in my shiny new lid, which can be used to top up the alcohol in the finished jar in the future if the level gets too low, without having to go to the hassle of removing the lid (which will be well sealed).

I also started a new project, which is this little chap:

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He is a small monitor lizard (of the genus Varanus), and he has clearly been squashed into a jar that was too small for him, as he is rather hunched and his tail curls around quite a lot. His main problem, however, was that the fluid level in his jar was far too low, as you can see above. He was still fairly flexible, so I didn’t need to put him into Decon-90, but instead moved him into a nice, new, (and much larger) jar and doused him in his first batch of IMS.

Tomorrow I will finish moving the frog and the lizards up the alcohols, mount the frog on his backplate, and attempt to re-attach some stray crab legs. Can’t wait!

Fun With Fluids

So, this week I am attending an excellent course in fluid preservation of natural history specimens run by Simon Moore. Handily, it is also being held at the Horniman this time round, so I don’t even have to go out of my way!

Day one featured a morning of lectures on the various problems that face fluid preserved specimens, including drying out, lipid contamination, and incomplete fixation. There was a lot of information to take in, and a lot of chemistry involved – I haven’t studied organic chemistry since university so I’m a bit rusty, and I can’t say I took in all of the details of fixative formulae and chemical reactions! But the theory was followed by practical, which always makes things clearer.

The practical side of the course involves rehydrating some completely dried out specimens. The first step was to choose specimens – I managed to bag myself a small, rather mouldy tree frog (of the genus Rhacophorus), and a jar of three crabs (labelled as Portunus depurator, now called Liocarcinus depurator, the harbour crab).

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My poor sad looking frog

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A jar of dry crabs

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The first step in rehydration is to bathe the specimens in a dilute solution of Decon-90 (which is usually used as a surface-active cleaning agent and radioactive decontaminant, but is also excellent for rehydrating dried tissues). I decanted the specimens from their jars into beakers, and placed them on hotplates to warm the Decon-90 solution slightly, which catalyses the reaction.

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And in their baths they will stay overnight, as my specimens remain quite stiff and unreponsive so far. Tomorrow they will be treated in a mild vacuum to remove the air pockets that are causing them to float at the moment.

While waiting impatiently for our specimens to show signs of improvement, Simon showed us some techniques for glass cutting, which is important for making new lids for specimen jars, and also showed us how to drill holes in jars to top up fluids without having to remove the lid (which is often quite a chore if the jar has been well sealed).

Charlotte demonstrating how to drill holes in glass

Charlotte demonstrates how to drill holes in glass

By the end of the week I hope my little critters will look plump, healthy and lifelike again! I will keep you updated on progress…

Museum of the Week #5

So, this past weekend found me back at the Natural History Museum. I went with a friend to see this year’s Wildlife Photographer of the Year exhibition, which, as usual, was excellent. I don’t agree with the overall winner (although the junior winner was definitely well deserved), but there were many beautiful and inspiring photos on display, and once again I found myself wishing I could take pictures that good.

While we were there, we also went on a free tour of the museum’s spirit collection (things preserved in alcohol (and ocassionally formalin)). The tour took us around the stores in the Zoology Spirit Building, which is part of the new (although I suppose it isn’t so new anymore!) Darwin Centre. The place is HUGE. There are whole floors filled with cabinets, stuffed with animals in glass containers of different sizes. We were allowed to see into a few cabinets, and were greeted by the watery stares of a bat, various rodents, and an upside-down tamandua.

We then moved into the tank room, which is the highlight of the tour. Here they keep all the really big specimens, including large fish, shetland ponies…and a giant squid (Architeuthis dux, nicknamed ‘Archie’ by The Sun newspaper apparently, despite the fact that the specimen is female!). The squid was really the main reason for our visit…having both read Kraken by China Mieville (a seriously weird, but very good, urban fantasy novel which features Archie herself and a cult of giant squid worshippers) we were really excited to see her. And she didn’t disappoint. Dominating the room in a giant glass tank, she is the length of a London bus. And she wasn’t alone – Architeuthis shares her tank with part of a colossal squid (Mesonychoteuthis hamiltoni, an incomplete specimen of which mostly tentacles survive). While not much of the colossal squid was present, the sharply hooked tentacles gave a very good impression of the predatory prowess of this little-known deep-sea cephalopod. There is debate about which squid is actually larger, as both are known from very few complete (and mostly immature) specimens.

The giant squid may be the main attraction of the tour for most people, but I was just as excited to see some of the tank room’s other residents, especially some very old specimens of Monotremes from 1880 with original hand-written on their jars proclaiming that these specimens were sent to Dr Owen for examination…Dr Owen of course being Richard Owen, famed anatomist and founder of the NHM. And then I got about as near to a religious experience as an athiest evolutionary biologist really can, when we were shown a small locked glass cabinet sitting nonchalantly in the corner of the room, containing specimens collected on the Beagle by Charles Darwin. Many of them had their lids painted yellow, which indicates that they are the type specimens for their species (the specimen used in the original description of a species, which holds the name, and against which all other specimens are compared). In the lab next door we also got to see a jar containing a small octopus which Darwin kept as a pet.

The spirit collection isn’t just there to look pretty (although it could be argued that some specimens are somewhat less than pretty!). It is an important research resource, and is regularly used by academics from all over the world who are interested in anatomy, taxonomy, evolution, and a whole host of other topics.

The tours on the weekend are only half an hour long, and give a brief introduction to the collections, taking in only a very few highlights. During the week they run longer tours – I might have to do one of those sometime, as I just love poking around in museum stores, and they don’t get much more exciting than the stores at the NHM.

Photos weren’t allowed on the tour, but there are also specimens on display in the public lobby of the Spirit Building. Here are a few tasters of this wonderful collection:

Fun With Fungi

Well, it’s been a busy few months…we are making headway on the Anthropology collections review at the Horniman: the team (we should really think up a cool team name!) has nearly finished reviewing the museum’s accession registers and cross-checking them against the contents of our collections management database, and next month we will be starting on the physical review proper (looking at all the objects and measuring, marking, photographing, etc. as needed). I’m looking forward to it, I love collections work. We’ve also started a Tumblr page, which we’ve been filling with pictures of amazing stuff we’ve found in the registers. You can check it out here: http://in-the-horniman.tumblr.com/, it gets updated regularly with new and brilliant things.

I’ve also been using a break from my Museum Studies course to gain new skills, some museum-related, others not so much. In the ‘not so much’ category falls archery, which I start tomorrow – I’m doing a beginner’s course with a club in London Bridge, and should be able to give Robin Hood a run for his money by Christmas! Or maybe not. More work-related are the field excursions I’ve been on with the London Natural History Society, which I joined in the summer to learn new field skills, and improve my ID skills for a variety of wildlife. And just to have fun – I’ve always been something of a theoretical naturalist, and it’s nice to be out in the field actually observing species in the wild.

Last weekend I went on a fungus forage at Bookham Common. I confess I know next to nothing about mycology, having studied a very small amount in my second year at undergrad, and I was very out of my depth. But the experts on our walk were all very kind about my total lack of knowledge, and very helpful in getting me up to speed. It was a lovely day, for the most part, and only rained a little in the afternoon. We were extremely lucky all round – it’s been a terrbile summer for fungus, having been mostly wet but then turning dry at the end of the summer, and there were fears that we wouldn’t find anything at all. But by the end of the day our list contained well over 100 fungus species, and everyone seemed pleased with the results.

I took a lot of photos (many of which are rather out of focus because the macro on my compact digicam is a bit poor). I’ve tried to identify most of them from the notes I made on the walk, and my shiny new Collins Complete Guide to British Mushrooms and Toadstools. Apologies to any mycologists out there if I’ve got any of them wrong! Corrections are gratefully received.

Science: Coming to a pub near you

I seem to have volunteered myself to be one of the speakers at a special PubSci event to celebrate Ada Lovelace Day. For those who don’t know (I confess I had to Google her), Ada Lovelace (1815 – 1852) worked on Charles Babbage’s early computer, the analytical engine, and wrote an algorithm designed to be processed by a computer – widely considered to be the world’s first computer program. In her honour, Ada Lovelace Day celebrates the contribution of women to science, maths, engineering and technology (STEM). The good people behind Science in the Pub are hosting an evening of feminine geekery on 16th October in the upstairs room at the Ritzy cinema in Brixton, which will feature a number of women talking about their careers and scientific heroines (it may also feature beer – this is optional). I’ll be contributing a short talk about women in palaeontology. If you like science, or beer, come along! It should be a fun night.

Know Your Enemy

Invasive species are a threat to our native wildlife. Some harbour disease, others compete with the locals for food and other resources, and still others predate on indigenous species.

The harlequin ladybird (Harmonia axyridis) originates in Asia. It was first recorded in south east England in 2004 (in the garden of a member of NatSCA!), and has since spread outward and upward to colonise the UK. In February of this year it was recorded in Shetland, completing its northerly journey in only 8 years. Harlequins are predators; they both out-compete native ladybirds for food, and also eat them if their usual prey – aphids and scale insects – becomes scarce. A recent study, which utilised public sightings of ladybirds reported to the UK Ladybird Survey, identified a dramatic decline in the populations of native ladybird species since the harlequin arrived, particularly the 2-spot ladybird (Adalia bipunctata), which had declined by 44% within five years of the harlequin reaching our shores.

So, you can imagine my joy when I discovered these little uglies on the nettles in my garden at the weekend (click on them for a better view):

Yep, harlequin larvae, pupae and adults. The full set. I instantly recognised the larvae as harlequins, as they are very distinctive with the orange stripes down their sides, and a brief internet search confirmed that the pupae and adults were also harlequins. The adults are harder to identify from a casual glance, as they are extremely variable in appearance. They are recognisable by their large size (although this is hard to judge without another ladybird sitting next to them for comparison!), and the patterning on the pronotum (the ‘neck’, if you like, between the head and wing cases). The pictures on this handy website are very useful for comparison with other species.

So, what do you think I should do with my little garden invaders? Should harlequins be exterminated one at a time, or is it now too little too late? How should invasive species be controlled (or even prevented from arriving in the first place)?