P'?3 
§ 3. Mr. Lewenhoeck indeed, fo near his Cotem- 
porary in this Difcovery as to claim a Priority, was 
much more advanced in Age and Experience j yet 
if he fhould alio appear to have been midaken, wc 
are not to be furprifed at it 5 for his repeated Ob- 
fervations upon the Sperm of fuch a Variety of Ani- 
mals, even as low as Infeds, feem to intitle him to 
draw Confequences as extenfive for a general Syf- 
tem of Generation, as his Experiments had been. 
In effed, what two more powerful Arguments 
could a Philofopher with the Knowledge of no 
other Fad, than that of their Exigence, have, than 
the Univerfality of Animalcules in this Fluid, and 
their feeming Confinement to this animal Secretion? 
§ 4. The Method of Reafoning by Analogy is but 
too apt to lead us into Miftakes, and therefore we 
ought to be very diffident of Confequences deduced 
this Way. Every new Appearance that has no known 
Caufe, immediately fixes, and but toooften at lad 
puts the Thoughts of the Obferver upon the Rack* 
When the Mind arrives at this Intenfity of Adion, 
how natural is it to free ourfelves from a painful Un- 
certainty at any rate, and that with as little Expencc 
of Refledion as may be ? The mod obvious and 
eafy Method is to clafs, if it admits it, and to re- 
duce it to fome other known 'Phenomena ; poffibly 
we are yet no nearer the phyfical Caufe, becaufe 
that of both is unknown. We have dill, however, 
the -Satisfadion to have diminiffied the Surprize it 
gives, by taking from its Singularity, and red in 
fome meafure contented with this little Deceit. 
§5.1 call it a Deceit, if we acquiefce in it, tillfuch 
time as a Number of Circumdances lhall concur to 
* 2 place 
