Sec. 20. However, he sharpned 'em again and renewed his Attempt with all the Skill he was Master of. At last he broke through, and the first part he met with was the Lungs, which he at first sight mistook, for that part which he search'd for, and turn'd 'em about this way and that way, to see if he could find in them the cause of the Disease. He first happen'd upon that Lobe which lay next the side [which he had open'd] and when he perceiv'd that it did lean sideways, he was satisfy'd that it was not the part he look'd for, because he was fully perswaded, that that must needs be in the midst of the Body, as well in regard of Latitude as Longitude. He proceeded in his search, till at last he found the Heart, which when he saw closed with a very strong Cover, and fastned with strong Ligaments, and covered by the Lungs on that side which he had open'd; he began to say to himself. "If this part be so on the other side as it is on this which I have open'd, then 'tis certainly in the midst, and without doubt the same I look for; especially considering the Conveniency of the Situation, the Comliness and Regularity of its Figure, the Firmness and Solidity of the Flesh, and besides, its being guarded with such a Membrane as I have not observ'd in any part." Upon this he searches the other side, and finding the same Membrane on the inside of the Ribs, and the Lungs in the same posture, which he had observ'd on that side which he had open'd first, he concluded the Heart to be the part which he look'd for. * * * * * [Illustration 4] * * * * *