Lester Smith was also in contact with Alex Todd. I imagine Alex Todd was a consultant advising them what they should do. Lester Smith at that time used to collect all the evidence that anyone else had collected who was working on B12 from our labs, whether they were working together or separately, and send them all to a small Glaxo group, which included Todd and myself.

[Q] Who did the crystallisation of that, Dorothy that led to the X-ray work being done? Was that you, or Lester Smith?

Lester Smith did, really, because he crystallised it from water, and just crystallised by evaporation, just like that.

[Q] Very simple.

And when he brought this preparation in, I just took a few crystals out of it that weren't good enough really to photograph, and put them in a drop of water, and then very beautiful, small crystals came out at the edge of the drop. And from these, you could see that it was extremely pleochroic. And I said, I can't understand Merck not saying in this letter to Nature that this compound was pleochroic. I expect the truth was they hadn't, they didn't use a mineralogist's microscope, so they didn't have crossed nicols or anything like that.

[Q] They couldn't have avoided it, could they?

Yes. It's really very beautiful. And I thought that would mean there was something like porphyrin ring in the molecule.

[Q] Was it known to contain cobalt then?

No, we had learned about the cobalt about a fortnight afterwards. Dr McCray, who was a researcher at Glaxo rang me up during lunchtime at home, and I was very lucky because I wasn't always at home for lunch - that day I was taking [unclear] home to lunch - and he rang us up and told us there was cobalt in the vitamin. And he said quite straight out, 'There's a heavy atom for you - you can work on this'. And, well, we knew the molecular weight about then, and it seemed to us cobalt was not really heavy enough in relation to the structure, but we tried nevertheless. And that was our first and earliest trouble.