De generatione was the last of the three works published by William Harvey during his lifetime. Although this work on generation was most ambitious, being the product of prolonged and detailed researches, it has received relatively little attention from modern writers. It is generally felt that this work, like William Gilbert's De mundo, departs significantly from the more pronounced empirical approach to science which characterized Harvey's first publication, De motu cordis. De generatione shows that Harvey regarded reference to teleological and vitalistic principles as necessary for the solution of crucial problems in biology. In this respect he differed from his contemporaries, the iatrochemical and iatromechanical physiologists, whose non-teleological approach seems, at least superficially, to be in sympathy with the modern biological tradition. The structure and content of De generatione are so evidently determined by Aristotle's biological writings, that the work is used to illustrate Harvey's failure to emancipate himself from the philosophical encumbrances of antiquity.

In France, as in other European countries, especially Britain and Germany, the nineteenth century was a period of great progress and achievement in science. This would still have been true if Claude Bernard and Louis Pasteur had been the only outstanding French scientists of the nineteenth century, whereas there were, of course, many others apart from an impressive number of brilliant French mathematicians. Nevertheless, although it was a great century for French science there was perhaps something rather disappointing about it, and something rather ingrowing about the attitude of French scientists towards scientific developments in other countries. For example, the French took it hard that the creator of the theory of evolution should have been an Englishman, remembering too late Darwin's predecessor Lamarck, and they certainly were very slow in accepting Darwin's theory of evolution.1 Again, the French may have felt that after the important contributions of French scientists such as Coulomb, Poisson, Biot and, above all, Ampère, the theory of electricity and magnetism which is today principally associated with the names of Faraday and Maxwell should have been created by a Frenchman. Once again this new theory was only accepted very slowly and hesitantly, and even unwillingly, in France—one thinks, for example, of the criticisms levelled at the theory by Pierre Duhem in his “The Aim and Structure of Physical Theory”.2 Of course it might be that if one knew how to weigh properly the various achievements of French scientists in different branches of science one would find that, allowing for her rather static population during the nineteenth century, the total contribution of France compared well with those of Britain and Germany. Nevertheless, in one case at least, that of theoretical physics, there seems to have been an unmistakable failure to live up to the promise of the beginning of the century. The purpose of this paper is to advance possible reasons to explain this failure.

By an ancient and honourable tradition, which began last year when I spared you this exercise, the President gives a Presidential Address only once during his term of office, on retirement. A presidential address in the summer season is a privileged occasion. Coming at the end of an active day, it is not the moment for a massive account of research. Rather it is an occasion when one may indulge with privilege in some directed impressionism, and that is what I propose to do.