50 Vegetable Organography and Physiology. 



varices have been made in the study of vegetable anatomy and 

 physiology, by the labors of De Candolle, Dutrochet, Lindley, 

 and, more recently, the interesting inquiries of Carpenter, as to 

 lead to the belief, that the day is not distant when the naturalist 

 will discover, from the study of vegetable life, an explanation of 

 the cause of many of those phenomena which have, hitherto, 

 baffled the inquiries of the animal physiologist. Already the re- 

 mark made by Cuvier, on the various forms and vital functions of 

 animals, may, with equal fitness be applied to those of the vege- 

 table kingdom ; that they "are so many kinds of experiments 

 ready prepared by nature, who adds to, or deducts from each of 

 them, different parts, just as we might wish to do in our own 

 laboratories, showing us herself, at the same time, their various re- 

 sults." This is, indeed, the only true method of studying phys- 

 iology : to listen to the language of nature, as she spontaneously 

 reveals her secrets, is far preferable to the inquisitorial method of 

 extracting them from her, by cruel experiments. 



But before we undertake a description of the organs of plants, 

 or of their functions, or attempt to trace the analogy which ex- 

 ists between the two kingdoms, vegetable and animal, it will be 

 necessary to make a few brief inquiries into the nature of the 

 primary tissues, which enter into the structure of the vegetable 

 formations. 



The primary tissues, or elementary organs of all plants, are 

 three in number ; the cellular tissue, the woody fibre, and the vas- 

 cular tissue, or spiral vessels. To these is sometimes added 

 another tissue, denominated ducts. Late inquiries, however, have 

 shown these ducts to be a variety in the form of the spiral vessels, 

 and to be identified with them. 



The cellular tissue enters into the composition of all vegetables. 

 It is composed of minute, transparent vesicles, or cells, the sides 

 of which are adherent to each other. These vesicles are exceed- 

 ingly minute ; varying in size, in different plants, from the 30th 

 to the 1000th part of an inch. They generally contain an elabo- 

 rated fluid, which circulates freely, in all directions, through the 

 vegetable membrane that forms the sides of these cells. But the 

 medium by which this circulation is carried on, has, for a long 

 time, engaged the inquiries of vegetable physiologists. The cells 

 do not communicate by any appreciable pores or fissures. Noth- 

 ing of the kind has ever yet been discovered, although they have 



