»n6 PHYSIOLOGICAL VIEWS. 



The absence of light is favourable to the germination of seeds } 

 for light acts upon plants in such a manner as' to take away oxygen 

 by the decomposition of carbonic acid gas, and to deposite carbon j 

 now this is just the reverse of the process required in germinationj 

 where the carbon must be evolved and the oxygen in excess. 



A certain degree of heat is necessary to germination. Seeds, 

 planted in winter, will remain in a torpid state ; but as soon as the 

 Avarmth of spring is felt, the embryo emerges into life. By increas* 

 ing heat, the vegetating process of seeds may be hastened ; thus the 

 same seed, which with a moderate degree of heat would germinate 

 in nine hours, may be brought to this state in six hours, by an in- 

 crease of temperature. Too great heat destroys the vital principle; 

 thus corn which has been roasted cannot be made to vegetate. The 

 process of malting consists in submitting some kind of grain, (barley 

 is most commonly used,) to a process which causes an incipient 

 state of germination ; this is done by moistening the grain, and ex- 

 posing it to a suitable degree of warmth ; as soon as germination 

 commences, the process is stopped by increasing the heat. The 

 taste of the grain is then found to have become sweetish. The term 

 mail is given to grain which has been submitted to this process. 

 When mixed with water it forms a sweet liquor ; and the fermenta- 

 tion of this liquor produces beer. 



There is a great difference in plants as to their term of germina- 

 ting ; some seeds begin to vegetate before they are separated from 

 the pericarp.* 



In the greater number of vegetables, however, there is no germin- 

 ation until after the opening of the pericarp and the fall of the seed. 

 The time at which different species of seeds, after being committed 

 to the earth, begin to vegetate, varies from one daj^ to some years. 

 The seeds of grasses, and the grain-like plants, as rye, wheat, corn, 

 &c., germinate within two days. The cruciform plants, such as 

 fadish and mustard, the leguminous, as the pea and bean, require 

 a little more time. The peach, walnut, and peony, remain in the 

 earth a year, before they vegetate. 



All kinds of plants germinate sooner, if they are sown immedi^ 

 ately after being separated from their pericarps. Many vegetables 

 preserve their vital principle for years ; some lose it as soon as they 

 are detached from their pericarps. This is said to be the case with 

 respect to coffee and tea. The seeds of some of the grasses, as 

 wheat, &c. are said to retain their vital principle even for centuries. 

 It is asserted that mosses, kept for near two hundred years in the 

 herbariums of botanists, have revived by being soaked in water. 

 An American writerf says, that " seeds, if imbedded in stone or dry 

 earth, and removed from the influence of air or moisture, might be 

 made to retain their vegetative quality or principle of life for a 

 thousand years." But he very rationally adds, "hfe is a property 

 which we do not understand ; yet life, however feeble and obscure. 

 is always life, and between it and death, there is a distance as great 

 as existence and non-existence." 



* In the month of January, on observing tlie seeds of a very juicy apple, wliich had 

 been kept in a warm cellar, I saw that they were swollen, and the outward coat had 

 burst; examining one seed, by removing the tegument and separating the cotyledonSj 

 I saw, by the help of a microscope, the embryo as if in a germinating state ; the rad- 

 icle was like a little beak 5 in the upper part or plume was plainly to be seen the tuft 

 df leaves and the stem. 



t E. Barton. ^^___ 



The absence of light favourable to the germina'ion of plants— Heat— Effects of too 

 great heat exemplified in the process of malting — Malt— Season of germinating — Time 

 of germinating varies— Vital principle of fruits. 



