184 THE FLORIST AND 
Odors are distinguished into permanent, fugitive, and intermittent. Per- 
manent odors are such as are enclosed in the tissues of the wood and bark 
of plants in a concentrated form; and either from being but slightly 
volatile, or contained in close vesicles which prevent exhalation, they 
remain for a long time, giving to the organs in which they are contained 
their peculiar odor. There is probably no part of a vegetable absolutely 
destitute of permanent odor. Every variety of wood, under certain cir- 
cumstances, exhibits it. Some, nearly scentless otherwise, become strongly 
odorous when rubbed or heated. The Pine, Oak, and Beech, are examples 
of this kind. Others are odorous for a long time after being cut, under 
ordinary circumstances ; of this kind are the Rosewood of Teneriffe, the 
Cedar and Sandal-wood (Santalum album) of India, so highly esteemed 
in Eastern Asia for its fragrance. The slight volatility of the oil, to 
which these species owe their odors, and the compactness of the wood, 
enable them ^constantly to yield their fragrance for an indefinite length 
of time. 
Others are fragrant when first cut, but lose this property in a very short 
time, as is the case with the Cinnamon and Cassia, the fragrant substances 
being volatile, and the wood porous, both causes concurring to render the 
wood in a short time scentless. 
Fugitive odors are such as belong to organs of short duration, as the 
leaves and flowers, and we meet with them in the greatest abundance, and 
most frequently in the latter. All are aware that the flower is the source 
whence flows the delightful fragrance of the flower garden ; and during the 
season of the bloom of our Magnolias, the woods and swamps are perfumed 
by the odor of their flowers. It must have been remarked also, by the 
most heedless observer, that the odor of the garden, or forest of Magnolias, 
is much more pungent at some parts of the day than at others. During 
the direct action of the mid-day sun, little or no perfume is perceptible 
from either ; but as the sun sinks to the horizon, and the dews begin to 
settle on the leaves, the evening air becomes scented with their fragrance. 
The odor accumulates during the night, and as the dew begins to exhale 
with the rising sun, it is borne on the air in much greater abundance than 
at any other hour. Thus these silent worshippers pour forth their incense 
in a morning sacrifice to Him who extends to them, as to all, his kind 
regards. 
A shower produces similar efi"eets. Who has not enjoyed the grateful odor 
exhaled from the flowers of the field or garden after a summer's shower ? 
The causes of these apparently great emissions of odor, under the cir- 
