GiM 



MK. .1. li. LAWES, DB. BILBEBT, AM) l)K. PUGH OS 



drawn. It would hardly be supposed that, under such circumstances, tin- pro© I 

 cell-formation could go on \\ ithout the assimilation of free Nitrogi a, provided any t 1 

 were exerted in the cell the tendency of which was to fix free Nitrogen in the organism 

 of the plant. 



Oik; fact, briefly alluded to above, we wish to call more special attention to, as afford- 

 ing strong evidence of* the absence of the power on the pait of these cereal plants to 

 appropriate 1'nc Nitrogen — namely, the very large development of tin- root, requiring 

 but little Nitrogen compared with that of other parts. It was observed, in the expe- 

 riments of 1 SOT, that several of the cereal plants developed a large proportion of root; 

 but the danger of accident in analysis was such, that we hesitated to double the ri>k of 

 losing- the entire result by analysing the root anil the portion of the plant above ground 

 separately. They were, therefore, thoroughly mixed, and the mixture was carefully 

 divided ; so that, in case of accident, a duplicate was at our disposal, and in case of all 

 going well, confirmatory evidence was obtained. So very marked, however, was the 

 great development of root in the cereals of 1858, that, in several cases, it was analysed 

 separately from the other parts of the plant. The remarkable result was obtained, that 

 this great root-development was carried on (in two, at least, out of the three instance^ in 

 question) with a consumption of an almost incredibly small amount of Nitrogen, as the 

 figures given in the following Table will show : — 



Table XIII. 



The large proportion of root and its small proportion of Nitrogen, as here exhibited, 

 are equally remarkable. Whether this great power of the plant to develop root be due 

 to the fact that the process of cell-formation in the root requires less of the nitrogenous 

 protoplasmic compound, or to the fact that, floating in water as these roots generally 

 were, that fluid facilitated the withdrawal of the nitrogenous constituents resulting from 

 the decomposition of protoplasma from the old cells, to form new protoplasma for the 

 more active cells, is a question which, though foreign to our present subject, is of con- 

 siderable interest in a physiological point of view. The fact that the roots from the 

 base of the stem penetrated the soil, giving oft' very few branches into it, but immedi- 

 ately on reaching the water at the bottom of the pot exhibited such a remarkable deve- 

 lopment (see Notes on taking up the Wheat Plants, Appendix, p. 560), is in favour 

 of the inference that the water afforded the necessary conditions for the character of 

 growth referred to. 



