68 FAMILIAR LESSONS IN BOTANY. 



168. It is during the earliest stage of germination that 

 we discern the important office of oxygen. It unites '.vith 

 the carbon of the plant and passes off as carbonic acid gas, 

 diminishing the carbon and leaving an excess of oxygen, 

 which now busily employs itself converting the amylaceous 

 (starch) contents of the seed leaves into sugar, food for the 

 future plant. When this is prepared the plant develops 

 into life. 



169. It is not by the direct agency of oxygen, though it 

 is the leading power, if we may so express it, that converts 

 the starch into sugar. Neither is this conversion confined 

 to seed leaves, but is performed in tubers, as in the potato, 

 etc. The agent for this transformation is originally oxygen, 

 but that, uniting with the nitrogen and carbon of the plant, 

 creates another substance, a sub-agent, known in chemistry 

 as diastase. It seems to have no office save this, and is 

 found only in one situation, immediately in the passage 

 between the cotyledon and the germ ; and in tubers, only 

 at the very base of the eye or sprout. 



170. It exercises no influence other than that above men- 

 tioned ; but chemistry has revealed to us few more power- 

 ful agents, converting as it does two or three thousand 

 times its own weight of starch into sugar, for the growing 

 plant. If you have not studied chemistry, I hope you will 

 very soon, for you will thereby gain a more perfect knowl- 

 edge of this important agent and its offices to the plant, 

 and also of what I shall further relate to you concerning 

 the chemical process of germination. 



171. Carbon, of which the greater part of all the sub- 



168. What do we discover in the earliest stages of germination ? With what 

 doe? the oxygen unite ? Forming what ? What becomes of the excess of oxy- 

 gen resulting from the diminution of carbon ? What does amylaceous mean ? 



169. Is it by the direct agency of oxygen that sugar is formed ? What is this 

 eub-agent called ? Where is it found ? Has it any other office or situation ? 



170. Give me a proof of its power. What study is necessary for the perfect 

 comprehension of this subject ? 



171. Of what is the greater part of seeds composed ? To what is carbon op- 

 posed ? Why does a housekeeper put up her vegetables iu salt ? 



