OAT OF ECONOMIC PLANTS. 295 



making their war clubs, and for many other purposes, as it takes 

 a fine polish. Their bark furnishes a dye, and the burnt ash is 

 made into soap. 



C. muricata, native of South India, is valued for its showy 

 wood ; its weight, however, forms an objection to its use. 



Oak Galls {fiucrcus infedoria), a tree, native of the Levant. 

 It produces the best Galls of commerce, which are used in 

 the manufacture of ink, and for dyeing purposes. They are 

 extraneous productions caused by the puncture of an insect, 

 a species of cynips, laying its eggs on the leaves and twiggy 

 branches of the tree, causing an unnatural growth, that becomes 

 a Gall, and contains the pupa of the future insect. They are 

 found abundant on oak trees in this country, well known as Oak 

 Apples, but not of the quality to be useful. They are injurious 

 to the trees.-^ 



Oat (Avena sativa), an annual corn-grass of which there are 

 many varieties, supposed to have in process of time originated 

 from the Wild Oat (A. fatua). Pliny and Dioscorides mention 

 it as being early known in Greece. It is extensively cultivated 

 in Middle and Northern Europe to the 60tli degree of North 

 latitude. Its entire grains form an important article of horse 

 food, and when ground, which removes the outer skin or husk, 

 they become oatmeal, which is used for making porridge and oat- 

 cakes, and forms a staple and nutritious food greatly used by the 

 people in Scotland. The entire grain cleared of its skin and 

 dried becomes the Emden Groats of the shops. By the grinding 

 and dressing of the meal the skins or husks of the grain are 

 removed, and may be considered useless ; but as there is always 

 more or less of the fine farina attached to them they are utilised 

 under the name of seeds for making the Scottish dish called 

 Sowans. The preparation consists in placing a quantity of seeds 

 in a tub or other large vessel, and pouring on them a quantity 

 of water. The vessel is then covered up and allowed to stand 

 two or three weeks. During that time the seeds are frequently 

 stirred up. The water then becomes of a turbid nature, and at 



^ Oak Manna {see Willow). 



