300 Britain's Heritage of Science 



lens. He gave the first description of astigmatism of the 

 eye, and showed how it could be corrected by tilting the 

 lens, through which the object is looked at; but Young 

 had only come across a slight case of the defect. More 

 pronounced cases require cylindrical lenses, as subsequently 

 shown by Airy (p. 120). He also laid the basis of the theory 

 that colour vision is due to retinal structure corresponding 

 to red, green, and violet, and applied it to the explanation 

 of colour blindness. Young advanced Physiology also in 

 other directions, and in the Croonian Lecture, delivered in 

 1818, he stated the laws covering the flow of blood to the 

 heart and arteries. 



Thomas Addison (1793-1860), from Cumberland, was a 

 brilliant pathologist, and owing to his not being a very 

 successful practitioner, lived almost entirely on his teaching 

 and hospital work. He was the first to employ electricity 

 in the treatment of various spasmodic disorders and heart 

 disease, and, together with John Morgan, he wrote the first 

 book in our language on the action of poisons on the living 

 body. He described pernicious anaemia, and in his work 

 " On the Constitution and Local Affection of Disease of the 

 Supra-renal Capsules," he described that disorder which is 

 always associated with his name. This book is now regarded 

 as the starting point of a long series of studies into the diseases 

 of the ductless glands. 



A third researcher from the north of England was Sir 

 William Bowman (1816-1892), born in Cheshire, the well- 

 known ophthalmic surgeon. He contributed much to the 

 science of physiology. He it was who discovered and 

 described striated muscle, basement membranes, the ciliary 

 apparatus of the eyeball; but perhaps he is best known for 

 his research on the kidney, his theory being that while the 

 tubules and plexus and capillaries are the parts mostly 

 concerned in the secretions of urea, lithic acid, etc., the 

 malpighian bodies were the organs which separated the 

 watery constituents from the blood. 



With the arrival of Michael Foster (1816-1907) in Cam- 

 bridge as Praelector in Physiology at Trinity College in 1870, 

 began an era of great activity in biological research in that 

 ancient University. This subject had been by no means 



