Page:Philosophical Transactions - Volume 004.djvu/203

 Force, necessary to give an opposite New Motion.

In this first Book, he illustrates all with Eighty Figures, contained in two compendiously contrived Plates: And doth, from their proper Principles, demonstrate many of these things, which Writers commonly Postulate, or take for granted; but which (to make a sure Foundation) ought to have been demonstrated.

He occasion of Writing this Epistle, was, That the Learned Dr. Willis in his Pathologia Cerebri undertakes to confure the Causes of the Hysterick and Hypochondriack Passions, as they are assigned by our Author in his Exercitations, concerning these two Symptons, published An. 1660. Who thereupon thought himself obliged to write this Defence, in behalf of what he had formerly delivered upon this Subject.

The Controversie, as to the former of these Passions, consists in this, Whether the cause of it is to he referred more immediately to the Genus Nervosum, and it be primarily a Convulsive Symptom, depending on the Brain, and the Nerves thereof; or whether it ought to be imputed to the Blood, rushing too impecuously into and stuffing up the Lungs? Hence