88 



THE RETURN OF THE SWALLOW. 



The theory of " heredity plus environment " supplies an answer in 

 general, but it is not explicit enough to be thoroughly satisfactory. 

 I am not going to theorise on the point, but would just say that 

 before the heredity theory can be accepted, proof should be forth- 

 coming that the swallow was originally an English bird, and that 

 it actually existed in these pre-glacial times. 



Addendum. 

 Dates of arrival of swallows at Baillieston House, Lanarkshire, 

 compiled by Mr. John Maxwell : — 



