ON PROP A QA Tl ON B Y SEED. 21 1 



first step in the progress of germination is to render carbon mucilaginous 

 and soluble in water, and so to cause the evolution of carbonic acid gas. 



Accelerating the Germination of Seeds. In ordinary practice this is 

 chiefly effected by the application of a higher degree of heat, as by 

 placing pots of sown seeds in hotbeds, or by immersing seeds in tepid 

 water, or by cutting or paring nuts, or gently fermenting them in heaps 

 of sawdust, as is frequently done with chestnuts, walnuts, acorns, 

 almonds, &c. On a large scale, both in the field and the garden, the 

 most common resource is steeping in warm water for a few hours, 

 which is found to bring up the seeds of barley, turnips, beets, parsnips, 

 onions, &c., when the soil in which they are sown is very dry, much 

 sooner than would otherwise be the case ; this is found to prevent 

 them from becoming a prey to insects or birds. The sowing of some 

 seeds before they are perfectly ripe has also been found to promote 

 their early vegetation. 



Various experiments have been made to accelerate germination with 

 different degrees of success. These all proceed on the principle that 

 germination cannot take place until the carbon of the seed is changed 

 into carbonic acid ; and as this can only be done by extraordinary 

 supplies of oxygen, the agents employed are such as have the power of 

 supplying that substance in greater abundance than water or air, from 

 which, under ordinary circumstances, the plant obtains it by decom- 

 position. Humboldt was the first to observe that watering with chlo- 

 rine induced speedy germination ; and as, according to the observa- 

 tions of Gb'ppert, iodine and bromine, in conjunction with hydrogen, 

 produce a similar effect, it appears that both these matters, as well as 

 the oxalic and other acids frequently applied for that purpose, hasten 

 the process of assimilation. It cannot be denied that all these sub- 

 stances accelerate germination ; but to the practical gardener they 

 must be considered as experiments unfit for general practice, for the 

 young plants thus called into existence most frequently become sickly 

 through the excitement, and die off, which cannot surprise us, as the 

 same effect is seen when plants of cold climates are reared too warmly, 

 and are not placed in a cooler situation after germination. 



Electricity and Alkalies as Stimulants to Vegetation. It is conjectured 

 that electricity causes or accelerates chemical decomposition. In experi- 

 ments made some years since by M. Maltuen, it was found that seeds 

 germinated sooner at the negative or alkaline pole of a galvanic battery 

 than at the positive or acid pole, and following up these discoveries by 

 enclosing seeds in phials of alkalies and acids, he found they ger- 

 minated quickly in the former, and with difficulty, and sometimes 

 not at all, in the latter. Connected with the same subject are the 

 experiments of Dr. Horner and Mr. Hunt, on the differently coloured 

 rays of the spectrum ; the violet or deoxidizing end produces a 

 chemical effect, similar to the negative or alkaline pole, and the red 

 end produces the opposite or acid effect, by the retention of the 

 oxygen. To test the nature of these theories, some very old spruce- 

 fir-seed was treated as follows : It had been three years out of the 

 cones, and some of it sown the year before this experiment only yielded 



