ANALYSIS OF THE LESSONS. xi 



ing. 434. What the living parts of a tree are ; their annual renewal. 435. 

 Cambium-layer or zone of growth in the stem ; connected with, 436. new root- 

 lets below, and new shoots, buds, and leaves above. 437. Structure of a leaf: 

 its two parts, the woody and the cellular, or, 438. the pulp ; this contains the green 

 matter, or Chlorophyll. 439, 440. Arrangement of the cells of green pulp in the 

 leaf, and structure of its epidennis or skin. 441. Upper side only endures the 

 sunshine. 442. Evaporation or exhalation of moisture from the leaves. 443. 

 Stomates or Breathing-pores, their structure and use. 444. Their numbers. 



LESSON XXVI. THE PLANT IN ACTION, DOING THE WORK 



OF VEGETATION. . p. 157. 



446. The office of plants to produce food for animals. 447. Plants feed 

 upon earth and air. 449. Their chemical composition. 450. Two sorts of 

 material. 451, 452. The earthy or inorganic constituents. 453. The organic 

 constituents. 454. These form the Cellulose, or substance of vegetable tissue ; 

 composition of cellulose. 455. The plant's food, from which this is made. 



456. Water, furnishing hydrogen and oxygen. 458. Carbonic acid, furnishing, 



457. Carbon. 459. The air, containing oxygen and nitrogen ; and also, 460. 

 Carbonic acid; 461. which is absorbed by the leaves, 462. and by the roots. 

 463. Water and carbonic acid the general food of plants. 464. Assimilation 

 the proper work of plants. 465. Takes place in green parts alone, under the 

 light of the sun. 466-468. Liberates oxygen gas and produces Cellulose or 

 plant-fabric. 469. Or else Starch ; its nature and use. 470. Or Sugar; its na- 

 ture, &c. The transformations starch, sugar, c. undergo. 471. Oils, acids, &c. 

 The formation of all these products restores oxygen gas to the air. 472. There- 

 fore plants purify the air for animals. 473. While at the same time they pro- 

 duce all the food and fabric of animals. The latter take all their food ready made 

 from plants. 474. And decompose starch, sugar, oil, &c., giving back their ma- 

 terials to the air again as the food of the plant ; at the same time producing ani- 

 mal heat. 475. But the fabric or flesh of animals (fibrine, gelatine, &c.) contains 

 nitrogen. 476. This is derived from plants in the form of Proteine. Its nature 

 and how the plant forms it. 477. Earthy matters in the plant form the earthy 

 part of bones, c. 478. Dependence of animals upon plants ; showing the great 

 object for which plants were created. 



LESSON XXVII. PLANT-LIFE p. i 6 6. 



479. Life ; manifested by its effects ; viz. its power of transforming matter : 

 480. And by motion. 481, 482. Plants execute movements as well as animals. 

 483. Circulation in cells. 484. Free movements of the simplest plants in their 

 forming state. 485. Absorption and conveyance of the sap. 486. Its rise into 

 the leaves. 487. Explained by a mechanical law; Endosmose. 488. Set in ac- 

 tion by evaporation from the leaves. 489. These movements controlled by the 

 plant, wbiYh directs growth and shapes the fabric by an inherent power. 490. 

 Special movements of a more conspicuous sort. 491. Such as seen in the so- 

 called sleeping and waking states of plants. 492. Movements from irritation, 

 and striking spontaneous motions. 



