Most (possibly all) historical instruments are missing pieces, whether literally in the sense that parts have been lost, or metaphorically in the sense that there are gaps in our understanding about matters such as use or history (an instrument’s “provenance”). The University of Toronto Chambers’ micromanipulator is incomplete in both these senses; It is missing several important components, and it is lacking important documentation about where it came from and how it was used. Here, I’ll discuss some of the physical parts that are missing as well as the resulting difficulties that one might face in restoring this instrument to (or, perhaps, representing its condition when) it was used. Next time, I’ll discuss how gaps in the historical record also play into the ambiguity surrounding the instrument’s original form.
Surviving trade literature makes it possible to know, in a general sense, what could be missing from this instrument. I am grateful for a photocopy of Leitz Pamplet 1086, published in 1926 just after the instrument was first produced commercially, that was sent to me by the Countway Library of Medicine at Harvard University. This pamphlet gives a definitive list of the components initially available from Leitz, and consequently the possible configurations of an early model Chambers’ micromanipulator.
The object itself also supplies important clues. While it was possible to purchase this instrument with a single manipulator mechanism (or “movement”), this instrument has two—a more expensive and versatile configuration. Marks on the instrument’s base also reveal the locations and footprints of several missing components. The rectangular imprint of a syringe holder shows, for instance, that the instrument was operated with an optional microinjection apparatus.
It is fairly easy to identify many of these missing pieces, but it is very difficult to know exactly what they looked like. I have found surprisingly few images showing a complete instrument. As is often the case with early scientific instruments, professionally made technical illustrations that were created early in the instrument’s development and commercialization were reused until they were thoroughly outdated. Along with a few other images, they nevertheless show an instrument that was frequently updated and modified.
Consider, for instance, the syringe holder—the piece of the microinjection apparatus that would have left the rectangular mark in the photo above. Below are five depictions of this part (no. 6 belongs to a more modern Leitz micromanipulator that someone is currently selling on on ebay for $10,800)
The syringe holder is a simple part—basically a sturdy clamp that places the plunger of a syringe within easy reach of the operator—yet each image shows a different design. Here is a 3d-printed version of the part that I made in 2012 with the help of Isaac Record at Semaphore Labs. Hopefully I’ll have an opportunity to do a second version with a few changes and a more convincing effort to match the grey-brown colour and smooth anodized surface of the instrument’s base.
As I’ll discuss in a future post, the Chambers’ micromanipulator (no doubt like many mass-produced technologies) was constantly being changed and improved, often in very subtle ways and for reasons that can only be guessed. In order to create a depiction of the completed instrument, you would need to show it at a particular moment in time that corresponds to the object that you’re working with. The less information is available, the more you will have to guess—the 3d printed piece above is really an embodied guess.
In addition to the difficulty of knowing what particular parts looked like, every instrument was configured according to the needs of local investigators. It was also equipped according to local resources and circumstances (available microscopes and so forth.) You can’t represent the instrument without representing one possible configurations at the expense of others. If you decide to represent what this instrument (i.e. the model purchased by the University of Toronto) was used for, you will need a great deal of knowledge about the instrument’s provenance—the topic of the next post.
I’ll finish here with a list of the pieces that could be seen as “missing” from the instrument as it was found. To put it another way, these are the parts that you would need to add to the existing instrument in order to create a reasonably convincing facsimile of this Chambers’ micromanipulator configured for use. I’ll eventually describe all of these bits in detail.
1) Pieces that would have come with the micromanipulator but are now missing:
– A syringe holder
– Two metal ‘pillars’ for holding flexible control shafts
– A small clamp for securing the flexible metal tube of the microinjection apparatus
– Luer fittings for the microinjection system
– Probably a holder for replacing microtools
2) Pieces that would have been supplied by the operator that were specifically necessary for this instrument:
– A glass moist chamber (most likely locally made, though available through Leitz)
– Locally made glass microtools, a 2cc glass Luer syringe
– A fine brass tube of the kind used for gas lighting and sealant for the microinjection system
3) Associated microscope equipment:
– A suitable research microscope (slightly modified with a split condenser)
– Appropriate oculars and objectives
– A suitable mechanical stage
– A microscope illuminator (possibly locally made)
4) Material to be observed:
– Prepared bacterial cultures/ single-celled organisms/ reproductive cells/ plant or animal tissues, etc.