INTRODUCTION. 25 



Caroline. This is, I suppose, neither more nor less 

 than what is commonly called the bark ? 



Mrs. B. On the contrary it is both more and less than 

 the bark. More, because the cuticle is extended over 

 every part of the plant ; it covers the leaves and flowers, 

 with the exception of the pistil and anthers, as well as 

 the stem and branches ; less, because the bark consists 

 of three distinct coats, of which the cuticle forms only 

 that which is external. The cuticle of a young shoot, 

 after it has been for some time exposed to the atmos- 

 phere, becomes opaque, dries, and distended by the lat- 

 eral growth of the branch, splits, and after a year or two 

 falls off. A second membrane is then formed by the de- 

 siccation of the external part of the cellular integu- 

 ment ; but it differs from the former in being thicker, and 

 of a closer texture. It is not furnished with pores, hav- 

 ing no other function to perform than to enclose a layer 

 of air, and preserve the internal parts from injury. This 

 envelope is distinguished from the former by the name 

 of epidermis. 



These general, though, perhaps, rather desultory ob- 

 servations will, I hope, prepare you for our next inter- 

 view ; when I propose to take a full grown plant, exam- 

 ine its structure, and explain the nature of those organs 

 by which it is nourished and preserved. . We shall begin 

 with the roots, and then proceed up the stem to the 

 leaves. 



Emily. I should have expected that you would have 

 commenced by the birth of the plant, that is to say, the 

 germination of the seed. 



Mrs. B. If the plant derives life from the seed, 

 the seed equally owes its origin to the parent plant ; and 

 as the preparation of the seed, by that beautiful and del- 

 icate system of organs, the flower, is one of the most 

 curious and complicated operations of the vegetable 

 economy, I think it more eligible to reserve it for the lat- 

 ter part of our studies. 



77. Over what parts of the plant does the cuticle extend 1 ? 78. 

 How is the cuticle described on being exposed to the atmosphere 1 ? 79. 

 How is the epidermis of bark formed; how does it differ from the cu- 

 ticle; with what is it furnished ; and for the performance of what office 

 is it designed^ 80. For what is this conversation intended to be pre- 

 paratory 1 ? 81. What different course of procedure does Emily say 

 she should have expected 1 ? 82. What answer does Mrs. B. make her 1 ? 

 3 



