186 THE FLOKIST AND 
out flashes or puffs of perfume, as its intermittent odors are called. 
" Morren observed in one case of a cut-flower, that it gave off puffs of odor 
every half hour, from 8 to 12 P. M., when it faded, and the smell became 
very slight. On another occasion, when the flower was left on the plant, it 
began to expand at 6 P. M., when the first fragrance was perceptible in 
the greenhouse. A quarter of an hour afterward the first puff of odor 
took place, after a rapid motion of the calyx ; in rather less than a second 
quarter of an hour, another powerful emanation of fragrance took place ; 
by 35 minutes past 6 the flower was completely open ; and at a quarter to 7 
the odor of the calyx was the strongest, but modified by the petals ; after this 
time the emanations of odor took place at the same periods as before." 
Many other cases might be cited of sing"lar phenomena, properly 
coming under this head. The odors in these cases are certainly developed 
or emitted on different principles, in the different cases under this variety. 
The explanations are entirely beyond our reach. There seems to be a 
specific action of the organs for the production of the odors, as there can 
be no glands discovered by which the odorous fluid is secreted. That the 
odorous fluid is emitted as it is generated, which of course must be periodi- 
cally, is rendered probable by the fact, that emission of carbonic acid took 
place in the same manner from the flower of the Cereus. 
Odors have also been classed, from their similarity of effect on the human 
system, into aromatic, stimulating, penetrating, and sweet, but the diffi- 
culty of fixing definite limits to the application of these terms renders the 
classification of little use. 
Schubler and Kohler have made many interesting observations on odors 
as well as colors. They found that, of the various colors of flowers, some 
are more commonly odoriferous than others, and that some colors are more 
commonly agreeable than others. 
Color. No. of Species. Odoriferous. Agreeable. Disagreeable. 
White, 1193 187 175 12 
Yellow, 951 75 61 14 
Eed, ...... 923 85 76 9 
Blue, 594 31 23 7 
Violet, .307 23 17 6 
Green, ' 153 12 10 2 
Orange, ; .... 50 3 1 2 
Brown, 18 1 1 
The white m^jst odoriferous and agreeable, the yellow and brown njiost dis- 
agreeable. — Prof. Darhy. 
