Chemistry of Essential Oils

LABIATE 217

COMPARISON OF THE PHYSICAL PROPERTIES AND THE CHEMICAL COMPOSITION OF
PEPPERMINT OILS DISTILLED FROM THE FRESH LEAVES, FROM THE TOPS,
AND FROM THE \ ENTIRE FRESH HERB AT THE VARIOUS STAGES OF GROWTH.

Description ofYear and

Material.

1909.

Budding stage:

Herb

Leaves.

Tops

Flowering stage:

Herb

Leaves.

Tops

fruiting stage:
Herb „.

Leaves

Tops

Physical Properties.

Colour. Odour, and

j. a.sie.

Golden-yellow ;

pleasant, faint

odour, slightly

pungent, cooling

taste

Straw coloured; frag-

rant but faint

minty odour; fatty,

pungent, slightly

bitter taste

Straw coloured; very

fragrant minty

odour; fatty, bitter,

pungent taste

Pale yellow ; agree-

able menthol-like

odour; pungent,

minty taste

Straw coloured; pleas-

ant, minty odour;

pungent taste

Straw coloured; flow-

ery odour; pungent

taste

Straw-coloured; very

flowery odour;

• minty, pungent
  taste
  Golden-yellow;
  pleasant, minty
  odour; minty, pun-
  gent taste
  Light straw coloured;
  pleasant, flowery
  odour; minty,
  slightly pungent
  taste

Specific

Gravity

1

0-9158

(^1) -9143
1
-9151
1
-9203
(^1) -9389
1
-9370
1
-9151
(^1) -9373
1
-9223
Rota-
tion,
ou mm
Tube.

- 9-2

-12-1

- 12

-10-6

-11

-10-3

-8-3

-9-6

-9-5

Refrac-

tion.

2

1-4738

(^8) 1-4713

•* 1-4718

1

1-4662

(^2) 1-4706
8
1-4732
8
1-4676

1-4730

1-4723

Solubil

ity in

80 per

Cent.

Alcohol.

Vols.

(^1) 1-4
5
1
6
1-2
(^6) 1-2

"1

5

-8

1-5

5

1 •

Chemical Composition

(per Cent ).

Free

Acid

[cetic)as A-

o-io

•014

•116

•21

•52

•48

•10

•32

•16

Ester

(Men-

thyl

(Ace-

tate).

6-72

9*9

8-84

7-07

17-3

15'9

12-37

19-8

15-56

Menthol.

Free.

30-1

37-7

31-8

46-5

141-7

37-75

33-8

37-58

34-8

Total.

35-39

45-67

38-76

52-09

55-38

50-29

43-58

53-18

47-08

1

At 22° C.

2

At 25° C.

3

Clear in excess.

4

6 Turbid in 3 volumes or more.

Turbid in 1 $ volumes or more. 6 Turbid in 2 volumes or more.