I had the pleasure of reading this email from the mercurial Claudio Stern on a chicken list about trying to source a new contrast agent for chicken embryo research. This was once a particular type of ink (note the detail – totally understandable – of both the previous and suggested new system).
From: Claudio Stern
Subject: [Chicken-genome] ink for chick experiments in ovo
Date: 11 April 2012 23:08:07 GMT+01:00
To chick embryology colleagues and other egg-ologists:
Those of us who do operations on embryos in the egg have been frustrated for some time because the well-established, standard ink used to improve contrast between embryo and yolk (Pelikan Fount India drawing ink) has no longer been made for the last several years. A few years ago we found a shop in the USA that still had some and we bought a dozen bottles. We reached our last bottle a few weeks ago and started to panic as there was no alternative on the horizon. Most other inks contain phenol and/or other nasty stuff and the embryos didn’t like it.
I am very happy to report that we have now found an alternative (actually two … read on):
The new ink is made by Windsor & Newton and is just called “black Indian ink” (1005030). A 14ml bottle costs £3.40 from a local shop near here, and it is also available in much larger bottles (about 200 ml?). It keeps forever at room temperature – do not freeze. It works just as well as the old one and appears to be non-toxic – dilute 1:10 or more if you like.
I’d be surprised if you can’t get this in other places including outside the UK as it is a well-known make but if you have to order it from here, the postcode of the manufacturers is HA3 5RH.
Before we found this we were playing with various alternatives and a very clever student (Lizzie Ward) had the idea of trying squid/cuttlefish ink. I went to the Italian shop and bought “Nero di Seppie” (which I sometimes use for cooking – lovely!). This can be diluted a lot, about 1:50 or more, and it works too. It smells a bit fishy but the embryos don’t seem to mind. Amazing. Nevertheless I think the Indian ink above is a better alternative (for the embryos that is – I much prefer my risotto made with the squid stuff).
I particularly enjoyed the squid ink part as the alternative solution, and how Claudio quite rightly considers this to be far better used for cooking than science.
For me, this is just one example of the myriad of details that any particular experimental system has to have straight. Unlike programming, where at least you have versioned tools/systems and, when there is an issue, one can rerun programs as many time as you like, with as many print statements as you like, debuggers etc. For experimentalists, external things – be it ink supplies, buffers, water ions or all sorts can change arbitrarily under you, and when things go wrong one has to patiently work out (usually over months) how to fix or route around it. It shows the creativity and dedication of scientists like Claudio (and Lizzie) and a little window into the world of the experimentalist.
(PS – I checked with Claudio that this was ok to post first)