395 
the individual life”; but that there are “slight variations 
in different directions (divergent) in the offspring from the 
same parents” ; in opposition to other methods in which 
the change is during the individual life.* 
Dr. Ray Lankester asserts that “ Change of structure 
acquired during life—as stated by Lamarck—is also a fact, 
though very limited.”f 
When we remember the fact of the stability of species, 
and its consequent immobility under certain conditions, it 
is quite possible that instances might be adduced to show 
that sometimes little or no change takes place during the 
lifetime of the individual upon the organism of the 
individual. In these cases we have no evidence of any 
transmutation at all, either by Natural Selection or by 
any other method. But, on the contrary, there are cases 
in which a rapid change does take place. 
It is generally easy to decide from what district the 
common oyster has been brought, each district having its 
distinctive form of shell. The shell of the Mediterranean 
oyster is especially distinguished by the prominent diver 
gent rays. Now it is reasonable to conjecture that external 
conditions produce these modifications of form. The 
hypothesis is one which it is not difficult to test, and 
which has been actually tested. 
“ With respect to the common oyster, Mr. Buckland informs me 
that he can generally distinguish the shells from different districts. 
Young oysters brought from Wales and laid down in beds where 
‘ natives ’ were indigenous, in the short space of two months begin 
to assume the ‘native’ character. M. Costa has recorded a much 
more remarkable case of the same nature, viz., that young shells 
taken from the shores of England and placed in the Mediterranean 
at once altered their manner of growth and formed prominent 
diverging rays like those on the shells of the proper Mediterranean 
oyster.”—(The Variation, vol. ii., ft. 280.) 
* Evolution and its Relation to Religious Thought, ft. 74. 
t Nature, vol. xxxix., ft. 428.