Gcrminalion of Seeds. 73 



state, and is conveyed through the vessels of the cotyledon to the 

 axis, and thence to the radicle and stem. On the quantity of 

 this food furnished depends the vigour with which the young 

 plant will shoot ; and, hence, the best means of reducing the 

 albumen of the seed or tuber into a soluble food in the speediest 

 manner, and in the greatest quantity, is the greatest desideratum 

 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 ne- 

 cessary, and likewise the exclusion of light. The air yields the 

 oxygen necessary in abstracting the carbon, in the state of car- 

 bonic acid, from the 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° is re- 

 quired to reduce starch to solubility ; and it is not exactly known 

 how so much 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 ex- 

 tracted ; and, to all perceptible causes, we must add that vital 

 energy so every where necessary, and so little known. In soils 

 which have been properly prepared, by being broken into very 

 small particles, confined air is generated, which so increases the 

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

 benefits of well-pulverised 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 moisture 

 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 benefited 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 embryo of the 

 tuber of the potato, as lately illustrated in the three last conse- 

 cutive springs, in which, from the drought and heat acting on 

 the substance of the newly cut tuber, without the advantage of 

 moisture, the albumen has not been reduced into a soluble food, 

 or in such small quantity as not to be sufficient to produce the 

 developement of the bud or shoot. 



