Whytt does not discuss the circulation of the blood as described by Harvey, he assumes it as an established dogma; he makes no allusion to any anterior suggestion of change in the calibre of vesscls; but he seems, chronologically, to hand down the light of Harvey's torch to these more recent days, in which Claude Bernard, Lister, Brown-Séquard, and others have shown, by their researches, the importance of the knowledge that we now possess of the vaso-motor systemi of nerves, and its effects upon the function and structure of organs; as well as its relation to the doctrine, diagnosis, and treatment of disease.
iii. Another illustration of Harvey's speculation, and forecasting of ideas, comparatively new to us, but occurring to him as the result of his observations on the mysteries of generation, will have special interest now. "Let physicians cease to wonder [he says] at the manner in which cpidemic, contagious and pestilential diseases scatter their seeds and are propagated to a distance through the air, or by some fomes,' producing diseases like themselves, in bodies of a different nature, and in a hidden fashion, silently multiply- ing themselves by a kind of generation, until they become so fatal, and, with the permission of the Deity spread destruc- tion far and wide among man and beast; since they will find far greater wonders than these taking place daily in the generation of animals." 15
We seem to hear in this sentence the thoughts suggested by the works of Pasteur, Koch, and many others; and while feeling with them, with Seneca (whom Harvey quotes), and with himself that there is truth in saying "agents greater in number and of more efficiency are required in the construc- tion and preservation of an animal than for its destruc- tion . . . .;" yet, following Harvey, as he followed Sencca in seeing the analogy between the origins of disease and the
15 On Generation, p. 322.
