C 53 2 ] 
belorcthc Liver, and is infcrtcd into the fame Place 
of the Aorta of the other. It was much larger than 
any other Artery in either Child, and bellowed 
Branches on the Stomachy Me [enter y , and Mtfo- 
colon-y being about five Inches long; for there were 
neither ctelinc nor mefetiteric Arteries, according to 
Nature in either Child. 
Ohfer vat ions. 
When fonie former Authors (before 'the Learned 
were fo happy as to know the Sweets of experi- 
mental Philofophy) endeavoured to account for 
monfirous Productions in the animal World, they 
could have recourfe to no other means to explain 
them, than to the then reigning Sy Items by which 
they ufually explained the Thtenomena of the natu- 
ral Generation of Animals ; and that was in general, 
that an Animal was produced by the Admixtion of 
the fuppofed feminal Matter of both the Parents; 
that the Quantity produced by this Commixtion 
was fuppofed always to contain only a Quantity of Par- 
ticles fufheient to produce a natural Foetus , by the 
Mediation of a certain plajlic Power, faid always to 
attend it, as well as any other natural Production in 
the World. 
Upon this Plan many little Alterations were 
made by fucceeding Authors, without differing 
widely from this general Notion ; all as liable to 
Objections, and as eafily refuted as the Source from 
which theyfprung. And notwithftanding the Truths 
that have it nee been traced out by later philofophi- 
cal Advances, leading to a more reafonablc Know- 
ledge of the SubjeCt, -yet there dill are fome who 
appear 
