Note 50 — PART FIRST. (continued 2)

But there is a still more egregious blunder, and this the more surprising as it has been very general among physiologists, viz. that when an artery branches into two the capacity of the branches taken together is greater than that of the trunk. This would make the whole arterial system one continued aneurism,51 and, instead of promoting the circulation of the blood, would in the most effectual manner prevent it. In what manner an error so extraordinary in its nature could pass the mathematical physicians of the last century, I cannot imagine; but certain it is, that, in the year 1780 or 1781, the Edinburgh College were schooled on this subject by one of their own students named John Theodore Vander Kemp, a Dutchman. This gentleman found, by accurate mensuration, that when an artery divides, if the diameters of the two branches are made the two shorter sides of a right-angled triangle, the diameter of the trunk will be the hypothenuse; and thus, as the areas of circles are to one another in proportion to the squares of their diameters, the sum of the areas of the two branches will be equal to the area of the trunk. On looking into Blumenbach’s physiology, I find the same remark.