246 Electric Currents in vegetable Structures. 



far chemistry will enable us to understand the rationale of 

 these changes, and account for the developement of electricity. 

 According to the analysis of Berzelius, the atomic constitution 

 of starch and sugar (hydrate or crystallised) is as follows : — 

 Carbon, 7 atoms in starch, 12 atoms in sugar. 

 Oxygen, "6 — 11 — 



Hydrogen,"l3 — 23 — 



If, then, we suppose, that 8 atoms of starch undergo decom- 

 position during germination, it will be found that their ulti- 

 mate elements will be sufficient, under a fresh arrangement, to 

 form 4 atoms of sugar (hydrated), 1 atom of acetic acid, 

 and leave such a residue of oxygen, hydrogen, and carbon as 

 to require the absorption of 10 atoms of oxygen from the 

 atmosphere to form 4 atoms of carbonic acid, and 3 atoms of 

 water. Thus, the 8 atoms of starch become converted into 



4 atoms of (hydrated) sugar, 



1 atom of acetic acid, 



4 atoms of carbonic acid, and 



8 atoms of water.* 

 It would be little short of excessive presumption, in the 

 present state of physiological and chemical science, to assert 

 that the above changes are really those which always, and only, 

 take place : I merely venture the above remarks because they 

 are consistent with every thing we are yet acquainted with on 

 the obscure process of germination, and serving, in the absence 

 of a better explanation, to account for the developement of 

 electricity during the growth of the embryo. 



In limiting myself to the changes peculiar to the starch 

 during germination, I have, of course, noticed but one of the 

 vast series of chemical changes proper to vegetable existence : 

 still they are more than sufficient to account for the supply of 

 electricity in the interesting experiments of M. Pouillet; for, 

 if we take as an instance but one of the changes already alluded 

 to, common to the infant and adult plant (viz. the formation 

 and decomposition of carbonic acid), we shall find that the 



# This reasoning will be rendered more evident to the chemical student 

 by the aid of the following formulae : — 



8 atoms starch = (104 II. + 56 C. + 48 O.) 

 4 atoms sugar = ( 92 II. + 48 C. + 44 O.) 

 Then, (104 II., 56 C, 48 O.)— (92 H., 48 C, 44 0.)=(12 H., 8 C, 4 0.), 

 which represents the composition of acetic acid (6 H., 4 C, 1 O.)4-(0 II., 

 4 C, 1 O.), which requires the addition of (10 O.) to be entirely converted 

 into 4 atoms of carbonic acid and 3 atoms of water, or 4 (C. + 2 O.) -j- 3 

 (O. + 2 11.) 



N. B. In the above formulae, it will be observed that I have followed 

 Berzelius in the composition of water, and taken the double atom of hydro- 

 gen as unity. — G. If. 



