Notices respecting New Books. '27 i 



Dried seeds, although exposed to heat and air, may be 

 kept to any indefinite time, without eftectiiig a change in the 

 atmosphere, or undergoing any material disorganization. IF, 

 however, moisture have access to them, they immediately 

 begin to swell and germinate. Four or five days steeping in 

 water, at 46", or even 48 hours in temperatures from 60* 

 to GG", occasion putrefaction, carbonic acid and carburetted 

 hydrogen gases are produced, and the faculty of germinating 

 is destroyed. Hence it is concluded that water alone is es- 

 sential to germination, but if applied too long it disposes 

 to putrefaction. Besides water, a certain degree of heat is 

 necessary to the germinating process. Light has been con- 

 sidered another agent ; but, contrary to the opinion of the 

 abbe Bertholin, the experiments of Ingenhousz and Senne- 

 bier controvert this supposition, by showing that light occa- 

 sions evaporation, generates cold, and thus retards vegeta- 

 tion. However, although water and hear, appear to be 

 the only agents essential to the beginning of germination, 

 after a certain period air becomes equally necessary. 

 According to the experiments of Achard and others, nitro- 

 gen gas, which forms nearly four-fifths of the atmosphere, 

 completely obstructs germination and the formation of car- 

 bonic acid. Barley is converted into malt when exposed to 

 oxygen gas, which gradually disappears, and carbonic acid 

 takes its place; hence oxygen is likewise essential to the 

 process of germination. A great variety of experiments, 

 however, in different countries seem to establish as a fact, 

 that of all known gaseous bodies the usual composition of 

 the atmosphere is that which most facilitates a vigorous ger- 

 mination, a superabundance of oxygen as well as nitrogen 

 being injurious. From these data a curious and somewhat 

 difficult question arises, which the author discuiises with 

 great precision and accurate knowledge. The result of all 

 the experiments on germination proves that the quantity of 

 carboi.ic acid produced is very nearly in proportion to the 

 quantity of oxygen which dis;ippcar3 : hence it is asked. By 

 what process docs a pea immersed in water absorb oxygen 

 and disengage carbon ? Water alone neither absorbs oxygen 

 nor gives out carbon; and did the pea absorb oxvgen, it must 



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