TO 
JOHN FLEMING, D.D., 
PROFESSOR OF NATURAL SCIENCE, NEW COLLEGE, EDINBURGH, 
AND 
GEORGE JOHNSTON, M.D., LL.D., 
FELLOW OF THE ROYAL COLLEGE OF SURGEONS OF EDINBURGH, 
This Little Volume 
Is 
WITH GREAT ESTEEM AND AFFECTION 
DEDICATED 
BY THEIR GRATEFUL FRIEND, 
THE AUTHOR. 
