I probably changed subjects more than most. Nevertheless, in spite of a poor memory (when compared to the memories of my friends Bawden, Bernal, Miles, Haldane and Synge) and little manual dexterity, I moved reasonably smoothly along the scientific pecking order, while getting out of any subject as it began to get crowded. Such a system, or lack of system, may be epitomized as "Why do a job yourself if someone equally competent is ready to do it?" It can work— but, as with Batesian mimicry, only if it is not widely adopted.
Most research in universities and similar places does not have a clearly defined practical objective. When it has, the objective may be reached by fashionable procedures. But work along unfashionable lines is more likely to produce something unexpected and useful. Experiences in unconnected subjects may illuminate one another. That is why, as Seneca argues, innovations are more likely to be made by workmen than by philosophers. That was De Mandeville's thesis in The Fable of the Bees and, insofar as the dicta that Shakespeare gives to Polonius have a logical basis, it underlies his comment, "By indirections finde directions out."
Gregory Pincus was a fellow adopter of this system. During two periods when he worked in Cambridge, I found his company and his interest in all aspects of science, and in most other things, congenial. During a financial crisis in Harvard, similar to those afflicting UK universities today, he lost his job. After a period of some financial difficulty, he converted a magnificent mansion into a lab. This was financed by Worcester (Massachusetts, USA) businessmen and by government contracts. In 1946 he invited me to work in his lab for a year. The combination of escape from postwar austerity and Pincus' company was irresistible.
Most of the work in the Worcester Foundation for Experimental Biology was on the effects of stress on steroid metabolism. One technique involved putting rats to swim in a bath of cold water in the ladies' lavatory: oddly enough, scientists measured steroid changes in the rats only!
In spite of my ideological commitment to changing research subjects, the idea of becoming adequately informed about steroids was intimidating, and it was a crowded field. Hyaluronic acid had been a minor research topic in the Foundation. I had worked on Brucella antigens and on the constitution of agar, so I already knew some sugar chemistry.
Mammalian ova are encased in cumulus containing hyaluronic acid: sperm carry hyaluronidase. Only a bigoted antiteleologist could fail to suspect some connection, and to conclude that fertilization would be impeded if hyaluronidase were inhibited.
For many years I had been concerned about the nutrition of the poor in Britain in peacetime, all of us in wartime, and half the people in the world all the time. Hunger depends, among other things, on the ratio Number of People/Amount of Food. Having worked on the denominator, I thought it reasonable to work on the numerator.
So we made antihyaluronidases by the conventional technique of modifying the substrate. Partly nitrated hyaluronic acid was the most effective. It kept sperm from getting at ova in vitro, and was a contraceptive in rabbits. On the basis of these, and other, experiments, the Searle Co., which had financed my visit to Worcester, took out a string of patents.
That paper on preventing pregnancy in rabbits was Pincus' first on contraception. Having had his interest aroused, and having been harangued by me about food scarcity in much of the world, he thought about what could be done with steroids. Hence the Pill. Interest in hyaluronidase therefore waned.
A contraceptive method involving a precoital insertion is obviously less acceptable than swallowing a pill or being injected periodically. Today however the situation is changing. Anxiety about the side effects of tinkering with steroid metabolism may be excessive, but it exists. Attention is therefore reverting to other methods of contraception. Antihyaluronidases may deserve renewed attention. Those based on hyaluronic acid should harm mucosa less than unspecific inhibitors, and they should be cheaper because hyaluronic acid is abundant.
In 1951, Wilfrid Le Gros Clark and I edited a collection of 12 essays called Four Thousand Million Mouths (Oxford University Press) which argued that, with proper use of existing knowledge, enough food could be produced to feed the world adequately. Now that world population approaches 5,000 million, it is amusing to recall that half of the book's reviewers found our title and the opening words of the preface ("Within the lifetime of some of our children the world's population may be expected to reach 4,000 millions.") "alarmist.".
Although many wealthy countries are embarrassed by food surpluses, scarcities and famines are common elsewhere. These are partly caused by recent increases in population, which are partly caused by the commendable effort put into improving hygiene and medical services. Those allocating research funds should be constantly reminded that each infant life saved gives someone the job of producing the 20-30 tons of food that will be needed with reasonable expectation of life.
Furthermore, while few are satisfied with the medical techniques of last century, many are content with fuller exploitation of even older agricultural techniques. The most urgent need is for new techniques of food preduction which could be used by poor and relatively unskilled people in he villages where most of the hungry live. That re search field is still uncrowded.