A letter from Sir R- S- [i.e. Sir Robert Sibbald in defence of his "Scotia ilustrata, sive prodromus historiae naturalis."], to Dr. Archibald Pitcairn / [Sir Robert Sibbald].

Sibbald, Robert, Sir, 1641-1722

Date:: 1709

Credit: A letter from Sir R- S- [i.e. Sir Robert Sibbald in defence of his "Scotia ilustrata, sive prodromus historiae naturalis."], to Dr. Archibald Pitcairn / [Sir Robert Sibbald]. Source: Wellcome Collection.

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$your Aflertion • fince then there can be no ad- million of the Air into the Lungs, unlefs there be a precedent Dilatation of the Breaft *, that is, unlefs the Mufcles of the Breaft and enlarge its Cavity. 1 would know why thefe Mufcles fhould juft aft then and never before. There are feveral other Difficulties that occur in this Mat¬ ter $ but I will not trouble you with them at prefen t. In Page Sy.you undertake to anfwer fome Diffi¬ culties, as how fome fort of Animals that feem to he dead all the Winter, have yet Life and Re- ip] rati on $ and how it comes that in fome Dif- eafes a Man feetns to have loft both Pulfe and liefpiration, and yet is alive 3 and you fay both thefe Phenomena's may be eafily accounted for from this Dbfervation. Tbe Breaft of a Man you take to be a Sphe¬ roid, whofe leaf Diameter in thofe that are co?ne to their full growth, is about Fifteen inches. Whiljt the Breaft is dilated, the leffer Diameter is encreafed, and the bigger is not dhninijhed,\ and by that means the Cavity of the Breaft be¬ comes bigger. Suppofe the encreafe then from the Back Bone to the Sternum to be only the rlo of an inch, and then the encreafe of the Ca¬ vity will he 31 inches, and fo much Air will en¬ ter the Lungs when its Diameter is only en¬ creafed r~ of an inch : But ij the encreafe of the Diameter be £5 of an inch, the quantity of Mir drawn into the Lungs will be Sixty two inches. How the Breaft comes to be a Spheroid, I can't conceive. I have fome reafon to believe that it is not 3 becaufe Archimedes has demon- ic ftrated$