It is commonly counted among the many merits of our great countryman, Harvey, that he was the first to declare the opposition of fact to venerable authority in this, as in other matters; but I can discover no justification for this widespread notion.  After careful search through the “Exercitationes de Generatione,” the most that appears clear to me is, that Harvey believed all animals and plants to spring from what he terms a “primordium vegetale,” a phrase which may nowadays be rendered “a vegetative germ”; and this, he says, is "oviforme,” or “egg-like”; not, he is careful to add, that it necessarily has the shape of an egg, but because it has the constitution and nature of one.  That this “primordium oviforme” must needs, in all cases, proceed from a living parent is nowhere expressly maintained by Harvey, though such an opinion may be thought to be implied in one or two passages; while, on the other hand, he does, more than once, use language which is consistent only with a full belief in spontaneous or equivocal generation.[3] In fact, the main concern of Harvey’s wonderful little treatise is not with generation, in the physiological sense, at all, but with development; and his great object is the establishment of the doctrine of epigenesis.

[Footnote 3:  See the following passage in Exercitatio I.:—­“Item sponte nascentia dicuntur; non quod ex putredine oriunda sint, sed quod casu, naturae sponte, et aequivoca (ut aiunt) generatione, a parentibus sui dissimilibus proveniant.”  Again, in De Uteri Membranis:—­“In cunctorum viventium generatione (sicut diximus) hoc solenne est, ut ortum ducunt a primordio aliquo, quod tum materiam tum elficiendi potestatem in se habet:  sitque, adeo id, ex quo et a quo quicquid nascitur, ortum suum ducat.  Tale primordium in animalibus (sive ab aliis generantibus proveniant, sive sponte, aut ex putredine nascentur) est humor in tunica, aliquaaut putami ne conclusus.”  Compare also what Redi has to say respecting Harvey’s opinions, Esperienze, p. 11.]

The first distinct enunciation of the hypothesis that all living matter has sprung from pre-existing living matter, came from a contemporary, though a junior, of Harvey, a native of that country, fertile in men great in all departments of human activity, which was to intellectual Europe, in the sixteenth and seventeenth centuries, what Germany is in the nineteenth.  It was in Italy, and from Italian teachers, that Harvey received the most important part of his scientific education.  And it was a student trained in the same schools, Francesco Redi—­a man of the widest knowledge and most versatile abilities, distinguished alike as scholar, poet, physician, and naturalist—­who, just two hundred and two years ago, published his “Esperienze intorno alla Generazione degl’ Insetti,” and gave to the world the idea, the growth of which it is my purpose to trace.  Redi’s book went through five editions in twenty years; and the extreme simplicity of his experiments, and the clearness of his arguments, gained for his views, and for their consequences, almost universal acceptance.