42 
PROCEEDINGS OF SOCIETIES. 
those parts of plants which perform the most important offices in Vegetable 
Physiology, and hence the author is disposed to infer that nitrogen (being the 
element which more than any other is permanent in its character), when com¬ 
bined with residual matter, is the moving agent, acting under the living principle 
of the plant, moulding into shape the other elements. The method of ultimate 
analysis adopted by the author enables him, as he "conceives, fto detect very 
minute errors, and therefore to speak with certainty as to the accuracy and value 
of every experiment. 
June 21.— Francis Baily, Esq., V.-P. and Treasurer, in the chair.—The 
chairman announced that “Tier Majesty’s signature had been received in the 
Charter-Book as Patroness of the Society.” This we consider in the light of a 
distinguished honour conferred upon the Queen. A paper was read u On the 
Structure of Teeth, their Vascularity, and their Relation to Bones,” by John 
Tomes, Esq. Communicated by Prof. Bell. 
44 On the Evolution of Nitrogen during the Growth of Plants, and the sources 
from whence they derive that element.” By Robert Rigg, Esq. Communicated 
by the Rev. J. B. Reade, M.A., &c. 
In this communication the author follows up his inquiry into the influence and 
importance of nitrogen in Vegetable Physiology, by noticing, in the first place, 
the experiments of Dr. Daubeny, M. De Saussure, Sir PIumphry Davy, and 
those which he himself has made; all of which tend to prove that nitrogen is 
evolved during the healthy performance of the functions of plants; that the pro¬ 
portion which it bears to the oxygen given off is influenced by the sun’s rays; but 
that owing to the necessary exclusion of the external atmosphere, during the 
progress of the experiments, it is impossible, with any degree of accuracy, to 
calculate the volume of these evolved gases during any period of the growth of 
plants in their natural state. If to this indefinite quantity of nitrogen given off 
by plants there be added that definite volume incorporated into their substance 
and shown in the author’s former tables, the question arises, Whence do plants 
derive their nitrogen, and does any part of it proceed from the atmosphere ? A 
problem which the author proposes to solve by a series of tabulated experiments 
upon seeds, and seedling plants, indicating a large excess of nitrogen in the latter, 
and under such circumstances of growth that he is compelled to fix upon the 
atmosphere . as its source. By the same mode of experimenting, the author 
attempts to show that the differences which we find in the germination of seeds 
and the growth of plants in the shade and sunshine, are apparently due in a great 
measure to the influence of nitrogen. And he concludes by observing, that he 
does not touch upon the practical application of the subject , wherein the real value 
of the inquiry consists ; it is his object to draw attention to an element which, 
though in some instances so minute in quantity as to be with difficulty detected 
