IV ADVERTISEMENT. 



The Fourth Lecture was delivered January 20, ISVS, by 

 Dr. Horatio C. Wood, on " A Study of the Nature and Me- 

 chanism of Fever." Published by the Institution, February, 

 1875. 48 pp. 8vo. 



JOSEPH HENRY, 



Secreta7'y Smithsonian Institution. 



Smithsonian Institution, 



Washington, April, ISIt. 



