IV. THE BIOLOGICAL SCIENCES
By Professor Lawrence J. Henderson
AMONG the central problems of biology and scientific medicine, those which group themselves about the bacteriological and pathological investigations of Pasteur[1] have been very fully represented in The Harvard Classics. This is due partly to the fact that Pasteur, in providing an explanation of the conditions of life of micro-organisms and of the effects of their activities, contributed many missing links to the science of life, and unified our knowledge of the interrelations of living things. For, in its various ratifications and connections, Pasteur's problem is one of the most extensive, as it is one of the most important, in the whole domain of science. It includes or touches the subjects of fermentation and putrefaction, with the old problem of spontaneous generation and the whole question of genesis, the cause of infectious diseases and the manner of their communication, the nature and mechanism of immunity, including vaccination and antitoxins, and a host of other equally important matters. The work of Pasteur has led to modern surgery through the work of Lister,[2] to a large part of modern hygiene, sacrificing the lives of many investigators in the process; to new methods in chemical industry and agriculture, and it has created untold wealth and saved countless lives.
THE QUESTION OF SPONTANEOUS GENERATION
Aristotle, though his knowledge of embryology in at least one instance—that of the smooth dog-fish—was very great and very exact, appears at times to have been willing to assume spontaneous generation of such large animals as the eel, for instance, as a common occurrence. But there can be no doubt that even in antiquity common sense sometimes felt itself more or less in opposition to such an idea,
