IIED 



IIED 



ration, and by the slow conducting power 

 of an animal body, and, perhaps, by the 

 permanency of the enlarged capacity, 

 seems sufficient to account for the power 

 which animals possess of maintaining their 

 natural temperature, without any remark- 

 able change in an atmosphere greatly 

 heated, as was shewn in the experiments 

 of Fordyce and Blagden. (See Philos. 

 Trans. 1775.) It must be confessed, how- 

 ever, that some farther investigations 

 seem wanting on this subject. 



Though the lungs appear to be the 

 great organ of oxygenation in the larger 

 animals, it is well ascertained, that a pro- 

 cess of nearly the same nature is carried 

 on at the skin ; and in many of the smaller 

 or less perfect animals there appears to 

 be no other means for effecting this ab- 

 sorption. 



HEATH. See ERICA. 



HEAVINESS, in general, the same 

 with weight or gravity. See GRAVITY and 

 WEIGHT. 



HEBENSTREITIA, in botany, a genus 

 of the Didynamia Angiospermia class and 

 order. Essential character : calyx emar- 

 ginate, cleft underneath ; corolla one- 

 lipped, lip ascending, four-cleft ; stamens 

 inserted into the edge of the border of 

 the corolla ; capsule containing two seeds. 

 There are six species, all natives of the 

 Cape. 



HECTIC. See MEDICINE. 



HEDERA, in botany, English ivy, a ge- 

 nus of the Pentandria Monogynia class 

 and order. Natural order of Hederaceac. 

 Caprifolia, Jussieu. Essential character : 

 petals five, oblong ; berry five-seeded, 

 surrounded by the calyx. There are six 

 species, with several varieties. 



HEDERACEJE, in botany, the name of 

 the forty -sixth order of Linnaeus's "Frag- 

 ments of a Natural Method," consisting 

 of the ivy, vine, and a few other genera, 

 which, from their general habit and ap- 

 pearance, seem nearly allied. This or- 

 der consists of herbaceous and shrubby 

 plants, most of which, particularly the 

 ivy and vine, just mentioned, have creep- 

 ing branches, that attach themselves by 

 tendrils to the bodies in their neighbour- 

 hood. The roots are long ; the stems and 

 young branches commonly cylindric. The 

 leaves are alternate, sometimes simple, as 

 in the ivy and vine ; sometimes vyinged, 

 as in the zanlhoxylum, or tooth-ach tree, 

 in which the surface of the leaves is co- 

 vered with points. On each side of the 

 foot-stalk of the leaves of the vine are 

 placed two pretty large stipulze, tfr scales; 

 from the side opposite to the leaves pro- 

 ceeds a branching tendril, which serves ta 



fasten the plant to the bodies in its neigh- 

 bourhood. The flowers are either her- 

 maphrodite, as in the ivy and vine ; male 

 and female upon different roots, as in the 

 ginseng 1 ; or hermaphrodite and male up- 

 on different roots, as in the zanthoxylum. 

 The calyx, or proper flower cup, consists 

 of one leaf divided into five parts, which 

 are small, and generally permanent. The 

 petals are commonhv five ; but in the cis- 

 sus four, and in the zanthoxylum none. 

 There are five stamina ; but the cissus ha$ 

 only four. The anthers, or tops of the 

 stamina, are roundish : in the ivy they are 

 attached to the filaments by the sides, 

 In the zanthoxylum the filaments are 

 crowned with- twin anthers. The seed 

 bud is of different shapes ; the seed-ves- 

 sel is of the berry- kind, with one, two, or 

 five cells, and the seeds are from one to 

 five in number, placed either in distinct , 

 cells, or, as in the case of the ivy and 

 vine, dispersed through the pulp without 

 any partition See PANA'X, &c. 



HEDGES, in agriculture, are either 

 planted to make fences round inclosures, 

 or to divide the several parts of a garden. 

 When they are designed as outward 

 fences, they are planted either with haw- 

 thorn, crabs, or blackthorn ; but those 

 hedges which are planted in gardens, 

 either to surround wilderness-quarters, 

 or to screen the other parts of a garden 

 from sight, are planted according to the 

 fancy of the owner, some preferring ever- 

 greens, in which case the holly is best ; 

 next the yew, then the laurel, laurustinus, 

 phillyrea, &c. others prefer the beach, 

 the hornbeam, and the elm. 



HEDGE hog. See ERIJJACEUS. 



HEDGE sparrow, the brown motacilla, 

 white underneath, and with a grey spot, 

 behind the eyes. See MOTACILLA. 



HEDWIGIA, in botany, so called from 

 J. Hedwig, a genus of the Octandria Mo\ 

 nogynia class and order. Essential charac- 

 ter : calyx four-toothed ; corolla four- 

 cleft; style none; capsule tricoccous; seed . 

 a nut There is only one species, viz. H. 

 balsamifera, a lofty tree, more than sixty 

 feet in height, and nearly five feet in cir- 

 cumference, a native of St. Domingo. 

 The wood is used for many purposes : 

 the red gum that issues from the bark has 

 a strong aromatic smell, and is serviceable 

 in the cure of wounds : it is frequently 

 called bois cochon. 



HEDYCARYA, in botany, a genus of 

 the Dioecia Icosandria class and order. 

 Natural order of Scabridae. Urticae, Jus- 

 sieu. Essential character : calyx eight or 

 ten cleft ; corolla none : male, filaments 

 none : anthers in the bottom of the calyx. 



