116 THE LIFE OF A TREE. 
growing in some southern districts of England, 
which is invariably found upon a soil containing 
lime or chalk. Another of them, the bee-orchis, 
is often found in chalk-pits. In Switzerland a 
very beautiful plant of this species is found grow- 
ing upon the Alps. Whenever the soil contains 
limestone in this country, there the plant may be 
generally found. But as we travel on and enter in 
a region, which, though outwardly similar to the 
last, is found to contain a soil in which no lime- 
stone exists, there we cease to see the beautiful 
‘ Jady’s-slipper’”—the name of the plant,—until, 
continuing our travels, we come again to a lime- 
stone district, where we behold its striking 
flowers once more adorning the way-side. Again, 
Have none of our readers in their sea-shore wan- 
derings, fallen in with a peculiar class of plants 
which they will look for in vain in any other po- 
sition? Why is this? Undoubtedly, answers the 
chemistry of vegetation, because the salt matters 
contained in the sea-shore sand are necessary as 
a part of the food of these plants :—that this is 
really so we are able to illustrate by a little cir- 
cumstance, which came under our own notice. 
Having occasion to make some researches in 
