vm 
PREFACE. 
But these results are of little moment com- 
pared with those which are likely to accrue to 
animal life by the application of the same prin- 
ciple. This ulterior application has hitherto 
been considered more in the light of a philoso- 
phical abstraction, than as a fact of the highest 
practical importance. The beneficial influences 
of light, and of a pure and properly regulated 
atmosphere, have been, indeed, readily acknow- 
ledged by every physiologist, but have not yet 
received the attention which they deserve at the 
hands of the legislator, the medical man, or the 
scientific world at large. The Author first di- 
rected attention to this interesting subject in a 
lecture which Prof. Faraday did him the honour 
to deliver on the closed cases at the Royal Insti- 
tution in April 1838, and he has advocated the 
same cause on various occasions, especially with 
reference to light * in connection with the ques- 
tion of the abolition of the Window Tax. In 
the “ Illustrated Catalogue of the Great Exhi- 
bition,” the account of the closed cases was 
thus concluded : — “ The same pure and pro- 
perly moistened atmosphere which favoured the 
growth of the most delicate plants in the heart 
* See the letters of E. Chadwick, Esq., and Dr. S. Smith, in the 
Appendix; also, a letter to Sir Joseph Paxton in the Appendix. 
