106 



PROCEEDINGS OF THE 



periods of their growth, I gathered a number of leaves from 

 different trees and shrubs upon the 1st of June, keeping them 

 in a water bath at a heat of 212° Fah,, until they ceased to lose 

 weight, and I set down the loss by this means as moisture. T then 

 burned off the dry solid organic matter, and obtained the ash. 

 On the 1st of September I took leaves from the same trees, 

 before the leaves had began to change their colour, and submitted 

 them to the same operation ; the results are given in the follow- 

 ing table, reduced to 100 parts for comparison. And although 

 taken from a chemical standpoint, the results may not be without 

 interest to the Natural History Society. 



It would be unwise to draw conclusions from one course of 

 experiments under the same circumstances, but they are sugges- 

 tive. One thing is evident, that, independent of the important 

 functions which leaves play in the life of the plant, they also 

 accumulate and remove from it a large c^uantity of earthy matter, 

 that might otherwise clog up its life system. And they show 

 the necessity, when experiments are made for determining the 

 quantity of ash which different plants absorb and fix in their 

 system, of paying particular attention to the age of the jDlant, for 

 if, like the leaves, a young plant contains much less earthy matter 

 than an old plant, it may lead vegetable physiologists astray in 

 making their deductions. 



