138 PHYSIOLOGICAL VIEWS, 



You will recollect that in the process of germination, oxygen 

 gas unites with the carbon of the seed, and carries it off in the 

 form of carbonic acid. Air furnishes that important agent, 

 oxygen, which is the first moving principle of vitality. 



Carbon constitutes the greater part of the substance of seeds; 

 and this principle, being in its nature opposed to putrefaction, 

 prevents seeds from rotting, previous to their being sown. 

 Some seeds having an abundance of carbon, are capable of be- 

 in^ preserved forages; while others, in which this element 

 exists but in a small proportion, require to be sown almost as 

 soon as ripe ; and such as are still more deficient in carbon, 

 lose their vital principle, before separating from the pericarp. 



You can now understand that oxygen is important to ger- 

 mination, on account of its agency in removing the carbon 

 which held the living principle of the seed in bondage. 



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 de- 

 posite carbon ; now this is just the reverse of the process re- 

 quired in germination, 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 warmth of spring is felt, the embryo emerges into life. By 

 increasing IK at, seeds may be hastened in their vegetating pro- 

 cess ; ' thus the same seed, which with a moderate degree of 

 heat would germinate in nine hours, may be 1> this 



state in six hours, by an increase of temperature. Too great 

 heat destroys the vital principle ; thus corn which has been 

 roasted could never be made to vegetate. The process of malt- 

 ing consists in submitting grain of a certain kind, (that of bar- 

 ley is most commonly used,) to a process which causes an in- 

 cipient stage of germination ; this is done by moistening the 

 grain and exposing it to a suitable degree of warmth ; as soon 

 as germination commences, the process is stopped by increas- 

 ing the heat. The taste of the grain is then found to have be- 

 come sweetish. The term nialt is given to grain which has 

 been submitted to this process. When mixed with Welter it 

 forms a sweet liquor; and the fermentation of this liquor pro- 

 duces beer. 



There is a great difference in plants as to their time of ger- 

 minating ; some seeds begin to vegetate before they are sepa- 

 rated from the pericarp.* 



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



Oxygen an important agent Carbon The absence of light favourable to the 

 germination of plants Heat Effects of top great heat exemplified in the pro- 

 cess of malting Malt Season of germinating. 



