PREFACE. IX 



As regards foreign literature, I have scarcely had occasion to go beyond the 

 tolerably complete collection of works which (thanks to the vigilance of Messrs. 

 Williams and l^orgate) my private shelves contain ; but, in this connection, I beg 

 to offer my acknowledgments to D. ¥. Weinland of Frankfort, C. M. Diesing of 

 Vienna, E. Claparede formerly of Geneva, and R. Leuckart of Giessen, for their 

 kindly gifts. 



T. S. C. 



MiDDi/BSEX Hospital Medical College, London, 

 ■'- September, 1864. 



