ADDITIONAL PAPERS. 



Although the Society did not adjourn Hine die at its hist meeting, 

 owing to the indisposition of President Earle and other causes there 

 were no further. meetings held. This left a number of valuable papers 

 in the hands of the Secretary which had not been regularly pre- 

 sented, partly from the fact that they w^ere not accompanied by their 

 authors to have read them in person, and partly for the want of time. 

 They are, however, no less meritorious, and the Secretary in pub- 

 lishing them in this connection bespeaks for each that attention at 

 the hands of the reader that thev so well deserve. Secretaey. 



THE NUTRITION OF PLANTS. 



BV T. J BURRILL, PROFESSOR OF BOTANY AND HORTICULTURE, ILLINOIS UNI- 

 VERSITY. 



The water contained in living plants constitutes by far the greater propor- 

 tion of their weight. The amount is by no means constant in the same tis- 

 sues, much less the same in different parts of the same plant. A succulent, 

 growing shoot of a tree will lose nine-tenths of its weight by drying, while a 

 ripe seed from the same tree may not lose more than one-tenth, by the same 

 process. The wood of a healthy apple, or oak, loses by drying, at a tempera- 

 ture of boilmg water, nearly or quite one-half of its green weight; and what 

 will be surprising to some, the heart- wood will lose as much as the sap-wood, 

 except the cambium portion of the latter during or soon after the season of 

 growth. 



This large quantity of water exists as water, unaltered in any way, though 

 usually having dissolved in it several other substances. Yet the water is 

 essential to the physiology of the plant, not indeed as food, but for necessarj- 

 physical or mechanical processes of life and growth. If the amount of water 

 is much reduced by anj'^ means, the plant fiigs, or wilts; the cells lose their 



