. D&. Smith's Inirodu&ory Difcourfe. 17 
hitherto oppofed, I mean that of equivocal generation. ‘The meta- 
phyfical quibbles which had fo long difgraced the fchools, began 
now to give way to a fpirit of enquiry and obfervation ; but not in 
the {chools themfelves, for from thence light feldom fprings. The 
propofition of Harvey, % omnia ex ovo,” was not received without op- 
pofition; but this was forgotten in the much more furious oppo- 
fition given to his other more important and interefting doétrine, 
of the circulation of the blood. No fooner was this publifhed 
than a crowd of adverfaries befet him. — After in vain endeavouring 
to refute his opinion, they had recourfe to the common fubterfuge 
of denying its originality; taking upon themfelves the greater re- 
proach, of having been blind to the evidences already exifting of fo 
indifputable a truth, rather than allow their illuftrious SOL ROC 
any merit in the difcove al 
arvey begins what LEGE called 3i phy Mon period 
of Natural Hiftory. His hypothefis of generation was confirmed 
by the experiments of Redi and Malpighi, two very philofophical 
naturalifts, who have difencumbered fcience from many prejudices, 
and thrown much light on fome of the moft abftrufe parts of phy- 
fiology. The experiments of Redi to difprove equivocal genera- 
tion, are truly admirable, and Malpighi's inveftigations, relating to 
the anatomy and transformation of filkworms, and the develope- 
ment of the chick in the egg, are too celebrated to need any frefh 
eulogium. About the middle of the feventeenth century a new 
and very interefting propofition in phyfiology was ftarted, that of | 
the fexes of plants, the honour of which is given to our country- 
man Sir Thomas Millington. It is to be wifhed however that he 
had written fomething himfelf upon the fubject, or that we knew 
whether the idea were really originally his own. Nearly about 
the fame time the difcovery of the lymphatic veflels in animals was 
made either by Rudbeck or Thomas Bartholin, or rather by both 
D at 
