Vlll 
PREFACE. 
The child gathered the perfumed flower, not without pricking itself 
cruelly with the spines ; then, with its little hands still bleeding, it 
went to distribute roses to others in the room. 
“ Thou art now a vulgariser,” said he to the child, “ for thou takest 
to thyself the thorns, and givest the flowers to others !” 
The parallel, although exaggerated, is not without its basis of truth, 
and was probably suggested by the criticism some of his works have 
met with : the critics forgetting apparently that these works are an 
attempt to render scientific subjects popular, and attractive to the 
general reader. 
London. January , 18 ( 58 . 
W. S. 0. 
