ON PROPAGATION BY SEED. 



245 



564. Various experiments have been made to accelerate germination with 

 ditferent degrees of success. These all proceed on the principle that germi- 

 nation 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 suLttanee in 

 greater abundance than water or air, from which, under ordinary circum- 

 stances, the plant obtains it by decomposition. Humboldt was the first to 

 observe that watering with chlorine induced speedy germination ; and, as, 

 according to the observations of Goppert, 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 thes3 substances 

 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. Dr. Lindley, after quoting the experiments of Mr. Otto 

 of Berlin, who, by employing oxalic acid, made seeds germinate which were 

 from twenty to forty years old, and the statement of Dr. Hamilton, that he 

 had found a like advantage from the use of this acid (see the details in 

 Gard. ikfa^., viii., 196 and x., 368, 453), makes the following remark, appli- 

 cable also to the employment of a diluted solution of chlorine, as tried by 

 Humboldt : — Theoretically it would seem that the effects described ought to 

 be produced, but general experience does not confirm them ; and it may be 

 conceived that the rapid abstraction of carbon, by the presence of an imna- 

 turally large quantity of oxygen, may produce effects as injurious to the 

 health of the seed, as the too slow destruction of carbon in consequence of the 

 languor of the vital principle. (^Theory, S^c.^ p. 174.) 



565. Electricity and alkalies as stimulants to vegetation. " It has been 

 ascertained," Mr. Lymburn observes, " that electricity is connected with all 

 transformations or changes of organic substances, either as cause or effect ; 

 when electricity is present, it accelerates or causes chemical decomposition ; 

 and, according to Dr. Carpenter, when chemical decomposition takes place, 

 electricity is always developed ; though, perhaps, in most instances, it is 

 absorbed again by the new state of the compound. M. Maltuen, in experi- 

 ments made some years ago with seeds, found that they germinated much 

 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 germinated quickly in the former, 

 and with difficulty, or sometimes not at all, in the latter. Connected with 

 the same subject are the recent experiments of Dr. Horner, on the differently 

 coloured rays of the spectrum ; the violet or deoxidising end produces a 

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

 duces the opposite or acid effect, by the retention of the oxygen. Guided by 

 these theoretical opinions, I was induced to try their effects on some very old 

 spruce fir seed in 1836, which had been three years out of the cone ; the year 

 before, 1835, some of the same seed did not produce one-sixth part of a crop, 

 and I had good reason to suppose it would be worse the next. The year before, 

 when the seed was damped to accelerate germination, it had a musty fungous 

 smell ; and the seed leaves came up yellow, and, hanging by the ends in the 



