GROWTH AND HAEVESTING OF PERFUME PLANTS. 



33 



The decrease is so slight, however, as not to warrant the statement 

 that a consumption of odor has occurred. 



It must be understood that these results are proposed only tenta- 

 tiveh' and that further experiments will be carried on to prove or 

 disprove the conclusions drawn. 



Employing the aforementioned plants as typical examples, the 

 harvest j^eriod, in order to attain a maximum j^ield of oil with a 

 correspondingly high percentage of odorous constituents, should 

 begin as soon as the plant is fully blossomed. A delay of the 

 harvesting until the " after-flowering " stage is reached apparently 

 increases somewhat the quality of the odor, but this increase is largely 

 overbalanced by the decrease in the yield of oil, which is of para- 

 mount importance to the grower. 



The proper preparation of the material prior to distillation is not 

 to be overlooked, since the quality and the quantity of the oil are 

 varied considerably b}^ improper handling and by partial or com- 

 plete drying of the fresh plant before it enters the still. 



To illustrate this point more clearly, practical instances will be 

 mentioned to show the effect of drj'ing upon the quality and the 

 quantity of the oil from plants. The three examples previously men- 

 tioned will be used as a basis for the comparison of the oils from 

 fresh and dry material. In order to obtain a rational and logical 

 means for comparing the oils, fresh, green plants of peppermint, ber- 

 gamot mint, and wormwood were cut during the height of their blos- 

 soming stage. The herb in each case was divided into two equal parts, 

 one half of which was set away to dry and the other half distilled 

 immediately. The oils obtained were later analj'zed for the esters 

 and the alcohols, and the results obtained are presented in Table II. 



Table II. — Yield of oil and percentages of esters and of alcohols obtained from 



fresh and from dry plants. 



PEPPERMINT (MENTHA PIPERITA). 



BERGAMOT MINT (MENTHA CITRATA). 



Condition of plant. 



Date of distil- 

 lation. 



Fresh 

 Drj' . . . 



September. 

 December . 



Yield of 

 oil. 



Per cent. 



"1.30 



.75 



Linalyl 

 acetate. 



Per cent. 

 33.0 

 51.8 



Linalool. 



Per cent. 

 45 

 43 



195 



Calculated from dry weight. 



