OIL-BEARING PLANTS 



OIL-BEARING PLANTS 



499 



more than a century. It was introduced into the 

 United States at an early date and has been culti- 

 vated both in Europe and America on a commercial 

 scale. Formerly France was the chief producer, 

 but in the last fifteen or twenty years the United 

 States has held first rank as regards quantity dis- 

 tilled. The plant is grown chiefly in Michigan, 

 New York, Nebraska and Wisconsin. Good ordi- 

 nary farm land is chosen for wormwood, and when 

 in good tilth in spring is planted to wormwood 

 seed, usually in rows three feet or more apart for 

 easy horse cultivation, the plants being thinned out 

 in the row to a distance of eighteen inches to two 

 feet apart. The plants grow rapidly and yield a 

 considerable cutting the first year. By proper 

 weeding a wormwood-field will last three to five 

 years before it is plowed up and replanted. Some 

 growers sow the seed broadcast in pasture land 

 and harvest the wormwood, which is avoided by 

 the stock. This secures manuring of the crop. 

 The tops are cut for distillation in an advanced 

 flowering stage and the distillation is carried out 

 as in peppermint. The oil is dark greenish or 

 bluish brown in color and of a heavy consistency. 

 Wooden tubs that have been used in wormwood 

 distillation are not fit for use in distilling other 

 oils. The yield is about one-half per cent of the 

 weight of the fresh herb. In Michigan, in 1902, 

 90 acres yielded 873 pounds of oil, an average of 

 9.7 pounds of oil per acre. 



Wormwood is the active principle in the French 

 drink absinthe. In the form of this beverage and 

 as an oil it is capable in overdoses of producing 

 serious results resembling epileptic convulsions. 

 The oil distilled in America is in part exported. 



Plants Producing Fatty Oils. 



Many plants produce fatty oils in a very consid- 

 erable quantity and store these, usually in seeds or 

 fruits, as reserve food substance. They are used 

 at the time of germination as a source of energy to 

 support the young plant until it can maintain 

 itself. These oils are bland, usually lacking in any 

 very strong taste or odor when obtained in a pure 

 condition, and lack the strong antiseptic properties 

 which characterize the volatile oils. In their chemi- 

 cal relationships, they are closely allied to the com- 

 mon animal fats. In general they are all made up 

 of a mixture containing the same principal sub- 

 stances occurring in differing proportions.' In oils 

 having a low melting point, as olive oil, the pro- 

 portion of olein, the constituent having a low 

 melting point, is large ; in firmer oils this sub- 

 stance is present in smaller percentage, and the 

 constituents having a higher melting point, such as 

 stearin and palmitin, are present in large propor- 

 tion. This is true in the case of most firm fats, 

 such as cocoa butter, palm oil and the commoner 

 animal fats. Thus some vegetable fats are fluid at 

 ordinary temperatures while others are solid. 



Botanical source. 



Plants yielding fatty oils are widely distributed 

 through the vegetable kingdom. Among those sorts 



produced on a considerable commercial scale in the 

 United States, there are almost as many plant fami- 

 lies represented as there are oils. A few examples 

 will illustrate this : Cottonseed oil is obtained from 

 the seed of the species of cotton, Gossypium, be- 

 longing to the mallow family, Malvaeem; peanut 

 oil from the seed of Arachis hypogcea, the peanut, a 

 member of the pea family, Leguminosx ; corn oil 

 from the seed of the common field corn, Zea Mays, 

 of the GraminecB, or grass family ; linseed oil from 

 the seed of Linum usitatissimum, the flax plant, of 

 the flax family, Linacece ; rape-seed oil from Bras- 

 siea Napus, a member of the mustard family, Cru- 

 cifercB ; and castor-oil from the seed of Ricinus 

 communis, a member of the Euphorhiacem, the 

 spurge family. [Refer to the special articles on 

 these crops in other parts of the Cyclopedia for 

 further information.] 



Place of production in plant. 



As indicated in the above examples, the fatty 

 oils are found in seeds or fruits, where they are 

 stored in great abundance as reserve food products 

 for the use of the seedling during germination. 

 However, they are located in diiferent parts of 

 these structures. For example, in the seeds of the 

 castor-bean, peanut, flax and cotton, the oil is 

 stored in the germ, especially in the cotyledons. 

 The source of corn oil is found in the germ of the 

 corn grain, not in the storage tissue making up the 

 great bulk of the grain. In the olive, the oil is 

 stored in the fleshy pulp, of which the fruit in 

 large part consists, and not in the hard seed which 

 it encloses, therefore, not in the germ, as in the 

 other cases. 



Method of obtaining fatty oils. 



In order to obtain the oils from the seeds and 

 fruits in which they occur, it is necessary to break 

 open the cells in which they are stored and force 

 them out. This is ordinarily accomplished by the 

 application of high pressure. In some cases, when 

 not harmful to the oil, a moderate degree of heat 

 is employed, rendering the oil. more thoroughly 

 fluid, so that it will more readily run out. In some 

 cases, the heat developed by the energy expended 

 in securing a sufficiently high pressure is ample. 

 When the oil is expensive, the oil residues remain- 

 ing after pressure has been used^ are extracted by 

 the use of solvents. 



The residue left after the expression of the oil is 

 completed may be utilized, in most cases, either as 

 a stock-food, as in the case of cottonseed meal and 

 linseed cake, or as a fertilizer, of which cottonseed 

 meal is an example. 



Commercial information and uses. 



The production of plant oils of this class (the 

 fatty oils) in the United States on any considerable 

 commercial scale is limited to a very small number 

 of kinds : cottonseed, linseed, peanut, corn, castor 

 and olive oils. The magnitude of the production 

 of these oils or of the stock from which they are 

 derived is difficult to determine with any degree of 

 accuracy. 



