March 1907.] 



151 



Edible Products. 



in the Eastern United States. Here, too, after the harvest is gathered hogs are 

 turned on to the land, and grub up pods which have not been collected. As a green 

 manure for the tropics Arachis has been suggested, for it adds when ploughed in, 

 not only the materials drawn directly from the soil, but also the other food stuffs 

 taken from the air, including the nitrogen which the root tubercles acquire. 



Chemistry of the Seed. 



Analyses of the seed shew, as already stated, a richness in oil which varies 

 considerably. This oil is a non-drying oil, becoming turbid at+3° C, and congeal- 

 ing at— 3° C. It consists of the glycerides of four fatty acids, viz : — olein, arachin, 

 hj'pogaein, palmitin. The similarity of ground-nut oil to olive oil is apparent 

 when we remember that the main constituents of both are olein and palmitin. 

 Starch is present to a small amount. Albuminoid matter is more abundant, and 

 cane sugar has been detected (Schulze & Frankfurt in Zeitschr. fur physiolog. 

 (Jhemie, 1895, p. 511.) Oils, starch, and albuminoids when found in seeds are reserves 

 for the use ol the young plant and are absorbed in germination. Immediately 

 growth starts absorption of these products commences, and the chemistry of the seed 

 is considerably altered. In the place of the fats appear the corresponding fatty 

 acids and glycerine. Obviously oil extracted at this juncture will not have that 

 freedom from taste in which should lie its real value. 



We cannot record observations made directly on Arachis hypogoea but 

 analogy indicates that oleic, arachic, hypogaeie, and palmatic acids appear in the 

 seed when germination has commenced. The same acidifying process is produced 

 by fungi, and as these rapidly attack the seed rancidity is developed when they 

 are present. It is well known that seeds of many plants cannot be induced to 

 germinate until they have passed a certain period of quiescence. This is not so 

 with Arachis hypogoea. At any time a small amount of moisture is sufficient to 

 start the process ; so readily is it induced that occasionally in India germination 

 starts before the crop is dug. Germination started and then checked results in the 

 death of the seed. Such a dead and partly germinated seed contains rancid oil. 



A similar amount of moisture will favour the growth of moulds — Eurotium, 

 Penicillium, &c, — and these finding entrance into the tissues of the seeds by 

 bruised places add to the acidity. Unfortunately Indian nuts shelled by being 

 beaten and thus bruised, shipped or even stored damp, become rancid ; and experts 

 maintain that they can distinguish oil-cake made from this source by the 

 abundance of fungal threads in it. 



Ground-nut seeds do not require much moisture to stimulate growth, though 

 in the complete process of germination they absorb almost their own weight 

 (Bogdanow, see Just's Bot. Jahresbericht 1887 ', i., p. 207); light does not conspicu- 

 ously deter it (Pauchon in Ann. Sci. Nat., ser. 6. x., p. 98.) The great precautions 

 necessary to prevent growth in seeds reserved for sowing will be mentioned under 

 the head of cultivation. There is reason why the same precautions should not be 

 neglected in the case of seed destined for the oil-mill. 



Origin And Dispersal. 

 That Arachis hypogoea is of South American origin admits of no doubt. 

 Writers of fifty years ago, not as abundantly provided with evidence as we are, 

 incorrectly placed its home in the Old World. Those who wish to read the arguments 

 for its origin in America will find a masterly summary in De Candolle's Origine des 

 plantes cultivi'-es, to which very little can be added. When the Spaniards were 

 colonising the New World they found that the Indians knew and grew the plant, 

 and one, Oviedo, who was a director of mines in Cuba from 1513 to 1524, says that it 

 was very abundant in their gardens. How long they had grown it we cannot guess, 

 but we find evidence that it was more or less a staple food with them from the 



