Page:The growth of medicine from the earliest times to about 1800.djvu/419

 "heretics," let us remember, with a proper sense of shame, that we still have in our midst, in this twentieth century and in this "land of freedom," men of high social standing who are as virulent heresy-hunters as ever were the enemies of Servetus.

Experiments of Realdus Columbus.—Matthaeus Realdus Columbus, who was born at Cremona, Northern Italy, in the early part of the sixteenth century, acted for some time as Vesalius' prosector, and must therefore have had ample opportunities for acquiring a thorough knowledge of the experimental method of studying questions in physiology. He wrote a description of the pulmonary circulation which was more lucid and nearer to the truth than any which his predecessors had furnished. This description, which will be found in his treatise on anatomy (Venice, 1559), was based largely upon experiments that he carried out upon living dogs. As rendered into English from the French version supplied by Dezeimeris, it reads as follows:—

When the heart dilates the blood passes from the vena cava into the right ventricle; from the latter chamber it is pushed into the arterial vein (the pulmonary artery), along which channel it is carried to the lung, there to be properly thinned and mixed with air. Ultimately the blood passes on into the venous artery (= the pulmonary vein), the function of which vessel is to carry this fluid, now charged with air through the action of the lung, into the left ventricle of the heart. Then follows the contraction (systole) of this organ, as a result of which action the tricuspid valves rise up into position and form a dam that prevents the return of the blood into the vena cava and the pulmonary veins. Simultaneously with this action the valves placed at the opening which represents the commencement of the aorta (left ventricle), and those placed at the opening which corresponds to the beginning of the pulmonary artery (right ventricle), yield and thus open the way for the distribution of the blood throughout the rest of the body.

The reader will, I believe, admit that this description, while perhaps not faultless, is distinctly superior to that given by Servetus.

Columbus' experimental studies threw considerable light upon other matters relating to the physiology of the heart.