W. H. R. Rivers 
Medicine, Magic and Religion [PDF ebook] 
The FitzPatrick Lectures delivered before The Royal College of Physicians in London in 1915-1916

This is Volume IV of six in a series in the International Library of Psychology on Anthropology and Psychology. Originally published in 1924, this is a collection of the Fitzpatrick Lectures delivered before the Royal College of Physicians of London in 1915 and 1916 and it represents perhaps the first attempt to interpret with real knowledge and sympathetic insight the thoughts and ideas that find expression in Primitive Medicine.