442 Proceedings of the Ohio State Academy of Science 



Paris; practiced medicine for some years, writing medical 

 books meanwhile ; returning to theology again he was burned 

 at the stake in Geneva for heresy in the same year that he 

 published his Restitutio. While this work is a theological 

 treatise, it is of great interest to the physiologist for in treat- 

 ing of the vital spirit he describes the circulation of the blood. 

 He disagrees with (ialen from start to finish. According to 

 Servetus the blood does not pass through the septum but 

 passes from the right to the left ventricle by the way of the 

 lungs, through the pulmonary artery to the lungs and the 

 pulmonary vein from the lungs. Instead of the blood becom- 

 ing vitalized in the left ventricle, as Galen held, it is done in 

 the lungs. Servetus was the first to describe the pulmonary 

 circulation and the first to discard the idea of there being 

 holes in the septum for the blood to pass from one ventricle 

 to the other. In fact he says there is no blood passing in this 

 way. The idea of Servetus that the venous blood was changed 

 to arterial blood in the lungs was not understood nor appre- 

 ciated for more than a hundred years after his death. He also 

 states that the left ventricle is not large enough for this mix- 

 ture or elaboration to take place. This fact will be nc^^ed 

 again farther on in the paper. I will quote the passage in the 

 Restitutio that refers to the points in question. 



"For which purpose the substantial generation of the 

 vital spirit itself is first to i)e understood, which is composed 

 of and nourished by the inspired air and most subtle blood. 

 The vital spirit has its origin in the left ventricle of the heart, 

 the lungs aiding, to the highest degree, in its generation. The 

 spirit is subtle, elaborated by the force of heat, of a yellowish 

 color, with the power of fire, to the end that it may be, as it 

 were, a bright vapor from the pure blood, containing in itself 

 the substance of water, air, and of fire. It is generated, in fact, 

 in the lungs, with the mixture of inspired with the elaborated, 

 subtle blood, which the right ventricle of the heart communi- 

 cates to the left. Yet this communication is made, not ])\ the 



