INTRODUCTION

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BOTA AN Y.

BOOK I.

ORGANOGRAPHY; OR, OF THE STRUCTURE OF PLANTS.

CHAPTER I.

OF THE ELEMENTARY ORGANS.

Ir plants are considered with reference to their internal organization, they appear at first sight to consist of a vast multitude of exceedingly minute cavities, separated by a membranous substance; more exactly examined, it is found that these cavities have a variety of different figures, and that each is closed up from those that surround it; if the inquiry is carried still farther, it will be discovered that the partitions between the cavities are all double, and that by maceration in water, or by other methods, the cavities with their enclosing membrane may be separated from each other into distinct bodies. These bodies constitute what is called Vegetable Tissue, or Elementary Organs: they are the Similary parts of Grew.

The chemical basis of the elementary organs has been found to be oxygen, hydrogen, and carbon, with occasionally nitrogen or azote, combined in various proportions: their organic basis is solidified mucus, either in an independent state, or organized in the form of membrane and fibre.

Organic mucus has only lately been recognised as the pri

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