Associates - Todd Dinner, March 28, 1938. Speakers - Morgan, Borsook, Went, Pauling, Todd.

Ladies and Gentlemen: As a man who is neither a biologist nor an organic chemist, I feel rather out of place tonight. My only information about vitamins and hormones, aside from the stock in trade of the ordinary chemist, consists of one story, which I hope is new to some of you. It deals with the beautiful young lady who, to relieve a headache, took two aspirin tablets. On feeling worse, she looked at the label on the bottle, 'which read "Plantabs, the perfect plant food; each tablet is the equivalent of one shovelful of fresh manure."

Instead of talking about "Vitamins - what they are and what they do," I propose to say a few words about "Vitamin chemists - what they are and what they do." These vitamin chemists are extraordinary individuals - they are organic chemists who find the usual types of organic chemical investigation too easy and insist on tackling the hardest job in the world.

[This paragraph was struck through by LP] The first step in the chemical attack on a vitamin consists in it separation from the original food stuff as a pure substance. This may be a hard job. Thus there was rejoicing in 1933 when a new method of extraction was found which gave 5 grams - a small spoonful - of vitamin B₁ from one ton of rice polishings.

The second step consists in finding what atoms there are in the molecule. This is an easy job, involving straightforward analysis. It is found that in the hydrochloride of vitamin B₁ there are 12 carbon atoms, 18 hydrogen atoms, one oxygen atom, four nitrogen atoms, one sulfur atom, and two chlorine atoms. C₁₂H₁₈ON₄SCl₂

This far everything has been plain sailing. The hard work starts with the next step - that of determining the way that these atoms are hooked to one another in the molecule, in order that the vitamin can then be made in the laboratory. The vitamin chemist became a man working a difficult jigsaw puzzle with invisible pieces, and simultaneously a detective seeking in the laboratory for clues as to how they fit together. This pursuit of the structure of molecules is enthralling, and it has been going on for a long time. In 1825 Faraday discovered benzene in a gas obtained by passing whale oil through a red hot tube. The benzene molecule is a simple one, containing six carbon atoms and six hydrogen atoms, yet it was not until 1865, forty years later, that the great chemist Kekulé, while dreaming of atoms, saw a chain of sic atoms, hand in hand, swing around and form a ring, and then, in his laboratory, prove that benzene contains this ring of six carbon atoms. The methods of vitamin chemists are those of the last century, but refined to the point that the immensely difficult problem presented by the B₁ molecule with its 38 atoms can be attacked. Even then the structure determination and synthesis required four years of work by a dozen able men, including Dr. Todd in Edinburgh and Dr. Buchman, who is now at the California Institute as a member of the Chemistry Department, in New York.

I have been talking so far about what the vitamin chemists do, and not about what they are. Instead we might examine a specimen - not a representative specimen, but one of the hardy Scottish variant of the species. In the ten years since Dr. Alexander Todd was graduated from the University of Glasgow he has studied at the Universities of Frankfurt am Main, Oxford, and Edinburgh, working on the colored substances in flowers, substances produced by microorganisms and other natural products, including vitamin B₁ and vitamin C. Dr. Todd has held various senior fellowships, including the Beit Memorial Fellowship, and was the recipient in 1936 of the Meldola Medal of the Institute of Chemistry. He is Reader in Biochemistry at the University of London and staff member of the Lister Institute of Preventive Medicine. I am pleased to introduce as the next speaker Dr. Alexander Todd.