16 STUDIES IN ADVANCED PHYSIOLOGY. 



so as to renew the spirit in the adjacent blood vessels and 

 to ventilate the mind. However, in the abysses of these 

 ventricles evil spirits often hide which make war upon our 

 own spirit, and which are not put to flight until the assist- 

 ance of the Holy Spirit is invoked. While consciousness 

 resides in the choroid plexus, faith resides in the heart, 

 because as faith is a fundamental virtue it resides where the 

 vital spirit is originally made." Strange that with such a 

 medley of beliefs, some of which seem to border on the 

 blasphemous in their material conceptions of the Holy 

 Spirit, there should be included in the plainest terms such a 

 wonderful discovery as the circulation of the blood through 

 the lungs. Servetus's book was at once seized as heretical, 

 and poor Servetus, surrounded by all the copies of his book 

 that could be found, was burned at the stake in 1553. Two 

 of these original books still exist, one at Paris and the 

 other at Vienna. 



FABEIC1US. 



The anatomists, Falloppius (whence the name Fal- 

 loppian tubes) , Botallus (duct of Botallus) , Varolius 

 (pons varolii) , Eustachius (Eustachian tube), and others, 

 whose names are familiar to us from anatomical struc- 

 tures that still bear their name, added to the science 

 of anatomy rather than physiology. However, in 1574 

 another important step forward was made by Fabricius, in 

 the remarkable discovery that the veins normally possess 

 valves. As it was found that these valves all opened 

 towards the heart, it seems almost impossible that Fabri- 

 cius should not have stumbled upon the fact of the circu- 

 lation of the blood as we know it to-day. But Fabricius 

 made the blood flow from the heart outwards, against the 

 valves, and he explained the valves, by saying that they 

 prevented the too rapid flow from the heart to the organs. 

 When there was danger of congesting the organs, the 

 valves tended to close and so shut off more or less com- 

 pletely the supply of blood to that organ. The idea of the 

 ( ( vital spirits ' ' taken in at the lungs was still unques- 



