The Food of Flanits. 333 
depressions, etc., in several directions. It seems probable 
therefore, that here, as in Hastern Canada, local glaciers de- 
scending from the higher gathering grounds towards the 
coast, as pointed out by the late Capt. Kerr, R. N.' were the 
principal agents at work. But from its insular position, 
and lying as itdoes in the track of the Arctic currents, the 
coastal areas, at least, must have been subjected to intense 
erosion from icebergs and floating ice. 
THE Foop oF PLANTS.” 
By D. P. PenHALiow. 
An old proverb informs us that one-half of the world 
continues in ignorance of how the other half lives. If we 
accept this in the broadest sense, as applying to all organic 
life, we have a present illustration of its correctness in the 
fact that, with few exceptions, man knows little or nothing 
of the vital processes upon which the growth of the 
members of the more humble vegetable kingdom depend ; 
and he thus fails to grasp a knowledge of those important 
laws by which plants are enabled to afford him an abun- 
dance of sustenance and raiment. It is in relation to 
purposes of nutrition, that plants may be considered to 
bear the greatest importance to man, and in this respect, 
they are to be regarded from a two-fold point of view. 
First, they convert the crude mineral constituents of the 
soil, which would otherwise be wholly unavailable, into 
forms which enable them to become of direct value for 
purposes of animal nutrition. They thus afford to man, his 
principal supply of food. But they also constitute the 
entire source of nourishment for those animals upon which 
man subsists, and through the medium of which they 
undergo further special modifications, by virtue of which 
' Ibid, p. 68. 
* Sommerville Lecture delivered March 28th, 1889. 
