298 Britain's Heritage of Science 



A name that is sometimes overlooked in the history of 

 British Science is that of Clopton Havers (? 1650/60-1702). 

 He was for a time educated at St. Catherine's Hall, Cam- 

 bridge, but left the University without taking a degree. 

 He took the M.D. at Utrecht in 1685, and practised in the 

 city of London. But he was an anatomist as well as a 

 physician, and was the first to give an adequate account 

 of the structure of the bone, and this in his chief anatomical 

 work " The Osteologia Nova, or some new Observations 

 of the Bones and the parts belonging to them." His name 

 is commemorated by the Haversian Canals, a name which 

 is still used to designate those smaller channels of the bone 

 through which the blood-vessels pass. 



British animal physiology, which had started magni- 

 ficently with Harvey, and had continued under Mayow, 

 de Mayerne and others, was carried forward by Stephen 

 Hales (1677-1761). He was a born experimenter, and, as 

 a student, worked in the " elaboratory of Trinity College," 

 which had been established under the rule of Bentley, ever 

 anxious to make his college the leader in every kind of 

 learning. We have said something about the contribution 

 of Stephen Hales to vegetable physiology, but he was no 

 less brilliant as an animal physiologist. In the second part 

 of his statical essays, entitled " Haemadynamics " (1733), 

 a real advance is recorded in the physiology of circulation. 

 Hales invented the manometer, with the aid of which he 

 was able to make quantitative estimates of blood-pressure, 

 and measure the velocity of the blood-current. He knew 

 how to keep blood fluid with saline solutions. He studied 

 the shape and form of muscles in contraction and at rest, 

 and had a considerable knowledge of secretion. He worked 

 much on gases and paved the way for Priestley and others 

 by devising methods of collecting them over water. Of 

 him, Sir Francis Darwin writes : 



" In first opening the way to a correct appreciation 

 of blood-pressure Hales' work may rank second in 

 importance to Harvey's in founding the modern science 

 of physiology." 



He was a master of scientific method and the greatest 

 physiologist of his century. There were, however, many 



