GERMINATION. 



53 



Fig. 8. 



ical action between the oxygen and the carbon, and tends to 

 volatilize the carbonic acid which escapes in the form of gas, 

 at the same time it excites the germ, and stimulates its devel- 

 opment. 



4. By abstracting a portion of the carbon from the mucilage 

 and starch, of which the seed is mostly composed, a sweetish 

 milky substance containing sugar is formed, which is the first 

 nourishment of the embryo plant. 



Here we may notice a very beautiful 

 provision ; the embryo rejects all nour- 

 ishment from the soil, but nature has 

 stored up in the seed itself, a most nu- 

 tricious substance, fully adequate to 

 all its wants. Fig. 8, h cJ, represents 

 the seed lobes containing the nourish- 

 ment of the embryo c a, with the fine 

 tubes which convey it to the germ. 



The radicle c, Fig. 9, gives the first indication 

 of vitality, expanding and bursting its envelopes^ 

 and at length fixing itself in the soil. The plum- 

 ula a, next unfolds itself, developing the rudiments 

 of leaf, branch and trunk ; finally the seminal 

 leaves gradually drop oflf, and the seed is converted 

 into a plant, capable of deriving nourishment di- 

 rectly from the soil, and from the atmosphere. 



5. During this process, the gluten of the seed is partially 

 changed, and forms a substance called diastase. This sub- 

 stance appears to act an important part. It has the power of 

 transforming starch, first into gum, and then into grape sugar. 

 One part of diastase will convert 2000 parts of starch into 

 this substance. The necessity for this change, is due to the 

 insolubility of the starch ; on which account, it cannot enter 

 into the circulation. The diastase is, therefore, formed at 

 the point where the germ issues from the mass of food, and 

 converts the starch into a soluble form, that it may be easily 



5 



