( 43 ) 



just quoted, i.e. exposing the heart of a dog and keeping up artificial 

 respiration. He saw that the blood in the pulmonary vein was 

 scarlet before !t reached the heart ; also that if the inflation of the 

 lungs by means of the bellows was stopped, the blood in these veins 

 became dark and venous. He even " perfused," as we now call it, venous 

 blood through the lungs, and saw that, as long as the lungs were kept 

 inflated, it flowed out by the veins scarlet in colour, but if no fresh air 

 was blown into the lungs, or if the lungs were kept distended with the 

 same air, it flowed out still as venous blood. He therefore concluded 

 that this change was effected in the capillaries of the lungs, and that 

 the change is effected by the air. This view was further strengthened 

 by the action of the air on the crassamentum of the blood outside the 

 body. He thought the blood was not merely exposed to air, but that 

 the blood took up some of the air. There was no question of the 

 blood taking up only one constituent of the air, for the composition of 

 the atmosphere had not yet been ascertained. These fundamental 

 and important views of Lower were largely neglected, and we find 

 even Haller opposed the views of Lower. 



About 1660 he seems to have perfected his method of trans- 

 fusion, and much stir was made about it in 1665. At this time 

 diseases were thought to be due to morbid qualities of the blood. 

 This method held out a hope to replacing bad blood by good. Lower 

 and Dr. Edmund King transfused blood in the human subject in 1668. 

 There is an account of the process in Phil. Trans. No. 12 and No. 20 

 (1666), giving a general notice of the operation of transfusion carried 

 out before the Royal Society in London and at Oxford. In France 

 the process was ultimately forbidden by law. 



Lower made estimates of the pressure exerted by the blood, 

 calculated the amount discharged at each beat of the heart, calculated 

 the work done by the heart, the velocity of the blood-flow in the 

 arteries, and in fact touched and investigated some of the most 

 important problems in hsemadynamics — a worthy successor of 

 Borelli, and precursor of Hales, Poiseuille, and Ludwig. He was a 

 worthy follower of Harvey, and followed his method — accurate 

 observation and experimentation. There is one interesting experi- 

 ment described by Lower and shown to the Royal Society on Oct. 

 17th, 1667 — "making a dog draw his breath exactly like a wind- 

 broken horse." He divided the phrenic nerves as they pass through 

 the thorax. In this paper he gives an admirable exposition of the 

 mechanics of the respiratory movements. Lower appears to me to 

 stand out as one of the most clear-headed and logical experimenters of 

 his day. 



