78 ON THE GERMINATION OF SEEDS. 



to arrive at in prosecuting our enquiries after the best method of 

 furthering the process of germination. The starch and sugar 

 must be reduced to mucilage ; and from an inspection of the 

 table, it will be found necessary that carbon must be abstracted, 

 and oxygen and hydrogen added ; and, accordingly, it is found 

 that in germination, carbonic acid gas is given off, the air is de- 

 prived of part of its oxygen, and water yielding hydrogen and 

 oxygen, is absorbed. Air, heat and moisture are all necessary, 

 and likewise the exclusion of light, The air yields the oxygen 

 necessary in abstracting the carbon in the state of carbonic acid, 

 from starch, and converting it into sugar and mucilage, which may 

 be familiarly illustrated in the sweetness of malting grain and 

 germinating potatoes. A heat of 160 degrees is required to re- 

 duce starch to solubility ; and it is not generally known how such 

 heat is generally acquired. The disengagement of the oxygen 

 sets caloric free, and hence seeds moistened and thrown into a 

 heap to germinate, are found to generate a great heat. Alkalies 

 are also found useful in furthering the process, and are generated 

 whilst it is going on. Perhaps, also, the starch is more soluble in 

 its state of combination than when extracted ; and, to all percep- 

 tible causes, we must add that vital energy so every where ne- 

 cessary, and so little known. 



In soils which have been properly prepared, by being broken 

 into very small particles, confined air is generated, which so in- 

 creases the heat as to be perceptible even to the touch ; and 

 hence the benefits of well-pulverized ground, and of covering 

 with pieces of glass, and flower-saucers, &c. to increase the heat 

 and retain the moisture, and thus further greatly the vegetation 

 of the seeds ; and hence the different quantities of heat and mois- 

 ture requisite for seeds, according as they are dry and farinaceous, 

 or oily and mucilaginous. Very dry farinaceous seeds, as the 

 acacia, and others of that tribe, are benefitted by immersion in 

 boiling water ; and hence the reason why either heat or moisture 

 of itself is not sufficient, and even hurtful if carried to excess, 

 either in the germination of seeds, or the bud or embyro of the 

 tuber of the potato, as late illustrated in the three last consecutive 

 springs, in which, from the drought and heat acting on the sub- 

 stance of the newly cut tuber, without the advantage of moisture, 

 the albumen has not been reduced into a soluble food, or in such 

 small quantities as not to be sufficient to produce the develope- 

 ment of the bud oT shoot. 



