338 BULLETIN OF THE 



to give the necessary molecular mobility, soon sending a rootlet 

 downward into the earth, and raising a stem toward the sur- 

 face, furnished with incipient leaves. Supposing the planted 

 seed to be a potato, on examination we should find its large sup- 

 ply of starch exhausted, and beyond the young plant, nothing 

 remaining but the skin, containing probably a little water. What 

 has become of the starch ? " If we examine the soil which sur- 

 rounded the potato, we do not find that the starch has been 

 absorbed by it ; and the answer which will therefore naturally 

 be suggested, is that it has been transformed into the mate- 

 rial of the new plant, and it was for this purpose originally stored 

 away. But this though in part correct, is not the whole truth : 

 for if we weigh a potato prior to germination, and weigh the 

 young plant afterw^ard, we shall find that the amount of organic 

 matter contained in the latter, is but a fraction of that which 

 was originally contained in the former. We can account in this 

 way for the disappearance of a i^art of the contents of the sac, 

 which has evidently formed the pabulum of the young plant. 

 But here we may stop to ask another question : By what power 

 was the young plant built up of the molecules of starch ? The 

 answer would probably be, by the exertion of the vital force : 

 but we have endeavored to show that vitality is a directing prin- 

 ciple, and not a mechanical power, the expenditure of which does 

 work. The conclusion to which we would arrive will probably 

 now be anticipated. The portion of the organic molecules of 

 the starch, etc., of the tuber, as yet unaccounted for, has run down 

 into inorganic matter, or has entered again into combination 

 with the oxygen of the air, and in this running down and union 

 with oxygen, has evolved the power necessary to the organization 

 of the new plant. . . . We see from this view that the starch 

 and nitrogenous materials in which the germs of plants are im- 

 bedded, have two functions to fulfil, the one to supply the pabu- 

 lum of the new plant, and the other to furnish the power by 

 which the transformation is effected, the latter being as essential 

 as the former. In the erection of a house, the application of 

 mechanical power is required as much as a supply of ponderable- 

 "" materials."* 



t Agricultural Report, for 1857, pp. 440-444. Ih May, 1842, Dr. Julius 

 R. Mayer publi.shed iu Liebig's Annalen der Chemie, etc., his first remark- 

 able paper ou "The Forces of luorgaulc Nature," constituting the earliest 

 scientific enunciation of the correlation of the physical forces ; and (if 

 we except the work of Seguin in 1839,) of the mechanical equivalent of 

 heat. {Annalen u.s.w. vol. xlii. pp. 233-240.) In September, 1849, 

 Dr. R. Fowler read a short paper before the British Association at Bir- 

 mingham, on " Vitality as a Force correlated with the Physical Forces." 

 (Report Brit. Assoc. 1849, part ii. pp. 77, 78.) In June, 1850, Dr. W. B. 

 Carpenter presented to the Royal Society a much fuller memoir " On the- 

 Mutual Relations of the Vital and Physical Forces." (Phil. Trans. R. 

 S. vol. cxl. pp. 727-757.) Neither of these essays accounts for the 



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