Chemistry of Essential Oils

260 THE CHEMISTEY OF ESSENTIAL OILS

The var. thyrsiflorum Benth. is known as the common white basil.

The var. album Benth. (Ocimum album L.; 0. laxum, 0. americanum)

is cultivated under the name of lettuce-leaf basil, while the var. crispum

(Ocimum crispum Thunb. ?) is grown under the name of curly-leaved

basil.

The authors treat in detail of the morphological and anatomical

conditions of the various degenerate species, and in conclusion describe

the different essential oils, of which the properties are summarised in

the table below.

The variety most suitable for cultivation is Ocimum crispum (curly-

leaved basil), because it yields the highest percentage of oil, while so far

as its odour is concerned the essential oil from this variety is not in-

ferior to the ordinary commercial product.

The oil from the lettuce-leaved basil (var. album) gives a slightly

cloudy solution with 70 per cent, alcohol; all the other oils give clear

solutions when mixed with from 2 to 3 times their volume and more of

70 per cent, alcohol. The methylchavicol (estragol) content of all the

oils (acertained by the determination of the methoxyl-group) was about

55 per cent.

Constants. Var. Thyrsiflorum.

Crop 1910.
1
<»i,o... ' 0-9168
aD
OD of the Acety
lated Oil
Daoo.
Acid Value
Ester Value

- 10° 52'

+ 1° 36'

1-488

2-8

5-6

E 8 1 e r-c o n t e n t
calc. as Linalyl
Acetate.
Ester Value after
Acetylation
Alcohol - content
calc. as Linalol

1-96 p. c.

116-9

35-19 p. c.
Yield... 0-0855 p. c.

Normal samples of

following characters:—

Specific gravity

Optical rotation.

Refractive index.

Acid value.

Ester „

Eeunion oil, which

following characters:—

Specific gravity.

Optical rotation.

Refractive index.

Acid value.

Ester

Crop 1909.

0-9125

- 11° 28'

+ 1° 34'

1-484

1-4

3-5

1-22 p. c.

114-8

34-50 p. c.

—

Ocimum Basilicum.

Var. Crispum.

Crop 1910.

0-9123

- 10° 30'

+ 0°30'

1-484

2-1

4-9

1-71 p. c.

116-9

35-19 p. c.

0-1285 p. o.

German or French

...

is derived from an

•

.. •

...

Var. Album.

Crop 1910.

0-8975

- 12° 54'

+ 0°2'

Var. Purpurascens.

Crop 1910.

0-8959

- 13° 52'

+ 1° 52'

1-479 1-477

0-7 3-5

7-0 9-8

2-45 p. c.

130-2

39-66 p. c.

0-0780 p. c.

3-43 p. c.

126-7

38'46 p. c.

0 0370 p. c.

Crop 1909.

0-9100

- 10° 14'

+ 3° 2S'

1-477

2-1

7-7

2-68 p. o.

117-6

35-43 p.o.

—

distilled Basil oil have the

. 0-900 to 0-930

• 6° „ - 20°
  . 1-4800 „ 1-4950
  1 „ 4
  2 „ 12
  unknown variety, has the
  . 0-940 to 0-990

• 1° „ + 12
  °
  . 1-5150 „ 1-5175
  1 „ 3
  8 „ 25