Page:The Harveian oration, 1873.djvu/55

 that Harvey never came upon the facts relating to the alterations of lung-substance being entailed by destruction of brain-substance, not difficult to be observed and reproduced, which we owe to Brown-Séquard, For if he had come upon them, how could he have explained them in the absence of the entire chain of connecting facts, in the forging of which chain so many successive workers—Purkinje, Valentin, Weber, Burdach, Stilling, and others—have all contributed links? Might not even Harvey, often as he withstood such temptations, have, nevertheless, in default of power to assign the real causes of such a phenomenon, been driven back upon some of those explanations which he himself so forcibly denounces in the words (Epistola Secunda ad Riolanum, p. 116), 'Vulgo scioli cum causas assignare haud norunt dicunt statim a spiritibus hoc fieri et omnium opifices spiritus introducunt, et ut mali poetae ad fabulae explicationem et catastrophen advocant in scenam.' It is a hard thing for any man to abstain from speculating as to the cause of any well-established phenomenon, especially