The Reason of this Necessity is the pressure of the External Air upon the Surface of the Body, from which it was defended by the Interposition of the Membranes, and the Humours contain'd, which are not so compressible as the Body of the _Fœtus_ it self. So soon therefore as the _Fœtus_ is excluded, and expos'd to the immediate contact of the ambient Atmosphere, the Vessels and all the Cavities of the Body must necessarily be so compress'd, that the Fluids can't have room for motion, and consequently the _Fœtus_ could have no Life, if Nature had not contriv'd by the motion of the _Thorax_ to remove and admit that pressure alternately, and thereby to impress a motion on the Fluids, which is the Spring of Life. But this motion of the _Thorax_ being any way suppress'd, the equal pressure of the Atmosphere on all parts, occasions a total Cessation of motion, which is Death. I shall prosecute this Subject no farther now, nor trouble the Reader with any Apology, for dissenting from those Great Men herein named; because, I hope, I have done it with Modesty, and all the Respect due to so great Authorities, and have assign'd nothing which is not Matter of Fact uncontroverted, or deduc'd from it by plain Mechanical Necessity. _Some Thoughts and Experiments concerning _Vegetation_. By _John Woodward_, M. D. of the College of Physicians, and R. S. and Professor of Physick in _Gresham College_._ The _Ancients_ generally intitled the _Earth_ to the Production of the _Animals_, _Vegetables_, and _other Bodies_ upon and about it; and that for that Reason 'twas, that they gave it so frequently the Epithets of _Parent_ and _Mother_[1]. They were of opinion, that it furnished forth the _Matter_ whereof _those Bodies_ consist; and receiv'd it all back again at their Dissolution for the Composure of _others_. Even those who asserted _four Elements_, supposed that the _Earth_ was the _Matter_ that _constituted_ those Bodies; and that _Water_ and the _rest_, serv'd only for the _Conveyance_ and _Distribution_ of that _Matter_, in order to the _forming_ and _composition_ of them. 'Tis true, _Thales_, a Philosopher of the first Rank in those early Ages, has been thought to have Sentiments very different from these; but that without just Grounds, as I think I have sufficiently prov'd in another Paper, which I am ready to produce.