204 MM. Garreau and Brauwers on Cell-formation, Growth, 



manner as diastase ; but, however great the number of successive 

 dilutions and precipitations which it was made to undergo, it 

 always retained a notable quantity of dextrine, which could be 

 estimated, by Fehling's solution, at a third of its weight. A 

 portion of the viscid matter in solution in water, filtered, gave 

 by evaporation a transparent residue, scarcely coloured, very 

 prone to decomposition, turning brown at 194° F., and which, 

 when calcined to whiteness, left a small quantity of ashes, in 

 which analysis proved the presence of phosphates of potash and 

 lime. According to this, the substance possesses exactly the 

 composition of a farina saccharified by diastase. This substance, 

 which is also found diffused throughout the proper tissue of 

 the radicle, may serve for the development of this organ ; and 

 this supposition gains a certain degree of probability from the 

 fact that it is accumulated in largest proportion in the extremity 

 of the radicle, the seat of the formation and enlargement of the 

 cells. 



It is true that, being soluble in water, it may, in case of heavy 

 rains, escape in part from this destination, in which case it 

 would have to be supposed that the excess of this aliment is lost 

 to the plant, and diffused through the soil, to form, as we shall 

 endeavour to show hereafter, what have been called the excre- 

 tions of roots ; but, though there seems to be some foundation 

 for this last conjecture, there is no doubt that this material 

 serves for the development of the central cells which are to ex- 

 foliate, since the latter are suspended and grow for some time 

 in the viscid medium, which alone retains them united to the 

 rest of the tissue. 



When the radicle of wheat, in the condition just indicated, is 

 examined with a sufficient magnifying power, the moment it is 

 moistened, and under the slight pressure of the covering glass, 

 the outermost coat is seen to fall away; the disjointed cells of 

 which it is composed separate from one another, and float com- 

 pletely isolated in the viscid matter. The cells, as we have seen, 

 are clearly distinguished, by their forms and larger dimensions, 

 from those which constitute the apex of the axis, appearing more 

 elongated the further they are placed from the curved line which 

 bounds this region, — a fact which indicates that they must ne- 

 cessarily originate at the confines of that line. 



The cells, transparent and full of granules which are coloured 

 yellow by iodized iodide of potassium, are pushed forward and 

 to the sides by the new formations. In proportion as they are 

 removed from the point where they are formed, they grow in all 

 dimensions, the nitrogenous granules they contain becoming 

 more rare; then they increase in length, and remain applied 

 upon the persistent portion of the epidermis, or more or less 



