VOLATILE OIL PLANTS OF THE UNITED STATES. 39 



production of this oil is confined almost exclusively to the State of 

 California, where the tree grows abundantly. The tree is not 

 cultivated as a source of volatile oil, but is extensively grown for 

 ornamental; fuel, and timber purposes. The leaves and twigs are 

 collected from the waste branches or brush resulting when the trees 

 are cut for timber or wood and used for the purpose of distillation. 

 The material selected for distillation may be coarsely comminuted 

 and the essential oil readil}' obtained therefrom by the usual method 

 of steam distillation. 



The yield of oil varies from three-tenths to four-fifths of 1 per cent, 

 according to the quantity of woody branches and twigs introduced 

 into the still with the leaves, the latter producing the highest 3'ield 

 of oil. The use of this oil is very general, and it is employed chiefly 

 as a therapeutic agent. From TO to 90 per cent of the oil consists of 

 eucalyptol or cineol, the chief constituent and the one to which its 

 valuable antiseptic properties are due. 



The waste leaves and branches accumulating when the trees are 

 cut for lumber or wood are not fully utilized. At points where a 

 considerable number of trees are being felled a distilling apparatus 

 could under favorable circumstances be profitably installed and suc- 

 cessfully operated at a very moderate expense. It has been estimated 

 that 2 tons of leaves and twigs will produce from 3 to i gallons of oil 

 at a cost of about $3 a gallon for distilling the oil.'' 



MONARDAS. 



Two additional plants possessing volatile oils of antiseptic value 

 and growing wild in the whole north-central portion of the United 

 States, from Pennsylvania to Minnesota, are wild bergamot {Monarda 

 fistidosa) and horsemint {Monarda punctata), belonging to the 

 Labiate tribe. These plants yield oils rich in antiseptic constituents, 

 the former producing an oil consisting chiefly of the liquid phenol 

 carvacrol, while the oil from the latter consists for the most part of 

 the crystalline phenol thymol. Both of these constituents are isomeric 

 in character and of equal value as antiseptics, the extensive use of 

 thymol for medicinal purposes being familiar to most people. 



"Wild bergamot and horsemint, owing to their hardiness, are capable 

 of profitable cultivation in the Xorth-Central States, where the 

 climatic conditions seem to be especially suitable for their growth and 

 for the production of oil. The whole fresh |)lant during its flowering 

 condition is generally distilled, the amount of oil obtained being 

 influenced by conditions of growth and culture, but averaging from 

 three-tenths to 1 per cent or more. The perennial nature of the plants 

 enables the grower to produce them from year to year with a mini- 



" Bulletin 196, California Agricultural Experiment Station, p. 34. 

 195 



