atural
order Rutaceae, containing two species in tropical Asia and one in west
tropical Africa. The plants are trees bearing strong spines, with
alternate, compound leaves each with three leaflets and panicles of
sweet-scented white flowers. _Aegle marmelos_, the bael- or bel-fruit tree
(also known as Bengal quince), is found wild or cultivated throughout
India. The tree is valued for its fruit, which is oblong to pyriform in
shape, 2-5 in. in diameter, and has a grey or yellow rind and a sweet,
thick orange-coloured pulp. The unripe fruit is cut up in slices, sun-dried
and used as an astringent; the ripe fruit is described as sweet, aromatic
and cooling. The wood is yellowish-white, and hard but not durable. The
name _Aegle_ is from one of the Hesperides, in reference to the golden
fruit; _marmelos_ is Portuguese for quince.

BAENA, a town of southern Spain, in the province of Cordova; 32 m. by road
S.E. of the city of Cordova. Pop. (1900) 14,539. Baena is picturesquely
situated near the river Marbella, on the slope of a hill crowned with a
castle, which formerly belonged to the famous captain Gonzalo de Cordova.
Farming, horse-breeding, linen-weaving and the manufacture of olive-oil are
the chief local industries. The nearest railway station is Luque (pop.
4972), 4 m. S.E. on the Jaen-Lucena line. The site of the Roman town
(Baniana or Biniana) can still be traced, and various Roman antiquities
have been disinterred. In 1292 the Moors under Mahommed II. of Granada
vainly besieged Baena, which was held for Sancho IV. of Castile; and the
five Moorish heads in its coat-of-arms commemorate the defence.

BAER, KARL ERNST VON (1792-1876), German biologist, was born at Piep, in
Esthonia, on the 29th of February 1792. His father, a small landowner, sent
him to school at Reval, which he left in his eighteenth year to study
medicine at Dorpat University. The lectures of K. F. Burdach (1776-1847)
suggested research in the wider field of life-history, and as at that time
Germany offered more facilities for, and greater encouragement to,
scientific work, von Baer went to Wuerzburg, where J. I. J. Doellinger
(1770-1841), father of the Catholic theologian, was professor of anatomy.
In teaching von Baer, Doellinger gave a direction to his studies which
secured his future pre-eminence in the science of organic development. He
collaborated with C. H. Pander (1794-1865) in researches on the evolution
of the chick, the results of which w