INTRODUCTION TO BOTANY. 7 
copious. The ninth and last book is upon gums, exuda- 
tions, and the means of obtaining them. It is much to 
be lamented, that neither Aristotle nor Theophrastus, 
whose mental abilities were of the first order, perceived the 
advantages that would accrue from a detailed description 
of natural substances, by which a student deprived of the 
vivd voce instruction of a master might be enabled to re- 
cognise them. 
he next author that occurs is Dioscorides. As a phy- 
sician, the object of Dioscorides being only the materia 
medica, he discusses each article used by medical practi- 
tioners in a separate chapter, and comprises the whole in 
five books ; in which, although the order is not very exactly 
kept, the vegetables are treated of as they are aromatic, 
alimentary, and medicinal. For the precedence of the 
aromatics two reasons may be given: one, the usual pre- 
ference given to objects of luxury above those of use; and 
the other, that the perfumers were the apothecaries of 
ancient times, and naturally affected those substances which 
formed the principal articles of their trade, especially when 
we consider the much greater use of perfumed oils and 
ointments by the ancients than by the moderns. His de- 
scriptions are chiefly respecting the colour, size, mode of 
growing as compared with other plants then well known, 
and therefore left undescribed. ‘Thus he says: Hyssopus 
is well known to all; and then having compared origanum 
to hyssop, he compares centaurium minus, tragoriganum, 
serpillum, marum, polycnemon, symphytum petrseum, 
ageratum, papaver erraticum, to origanum; so that the 
knowledge of all these plants are made to depend upon that 
of hyssop. Jn like manner ocimum is made a type for the 
knowledge of the first: sort of calamintha, acinum, oci- 
moides, crinum, solanum, mercurialis, and heliotropium ; 
although by the lapse of years, the ocimum of Dioscorides 
is now become uncertain, and of course the knowledge of 
the other plants is rendered unattainable. 
Although Columella and Cato among the Romans wrote 
‘on Husbandry, yet none of their works can be said to be 
botanical. Pliny the elder, who commanded the Roman 
fleet stationed in the Bay of Naples, and who perished in 
the year of Christ 71, in an attempt to explore an eruption 
of Mount Vesuvius, is the only author of that nation whose 
writings can be said to belong to the scope of our work. 
In his Historia Mundi, a vast encyclopedia, scarcely less 
varied than the world itself, he has treated from the 12th 
