17 



ABOU SCHOM. 



ABSORPTION. 



' Father Sickle-Bill,' the bill being curved like a sickle. The 

 ^Ethiopian name, A bou-Jfannet, means ' Father-John,' because, as 

 M. Dumont supposes, the birds arrive about St. John's day. 



The following is the earliest account that we have of the ibis, from 

 an eye-witness (Herodotus, ii. 76) : " The ibis is all over very black : 

 it has the legs of a crane, and a beak considerably curved : its size is 

 about that of a crex. Such is the appearance of the black ibis, which 

 fights against the serpents. But the other ibis, which is more of a 

 domestic bird (for there are two kinds), has the head and all the neck 

 bare of feathers : it is of a white colour, except the head, neck, and 

 the extremities of the wings and tail, all which parts are very black. 

 As to its legs and beak, it resembles the other kind of ibis." The 

 black ibis, according to Herodotus, devoured the winged serpents 

 which yearly attempted to make their entry into Kgypt from Arabia. 

 It is needless to add that these winged serpents are a fable. Strabo, 

 who himself wag some time in Egypt, gives the following account : 

 '* The ibis is the tamest bird of all : in form and size it is like the stork. 

 But there are two varieties of colour, one of which is that of the 

 stork, and the other is all black. Every street in Alexandria is filled, 

 with them, partly to the benefit of the citizens, and partly not. The 

 bird is useful so far as it devours all kinds of vermin, with the 

 garbage of the shambles, and the refuse of the eating-houses, &c." 

 Here Strabo makes no distinction between the two, except in colour, 

 and he describes both species as living on all kinds of garbage. He 

 has probably confounded the real ibis and the stork. 



ABOU SCHOM, the Arabic name of a species of fox (Canis 

 rariff/atut.) 



ABRAMIS. [BREAM.] 



ABRAXAS, a genus of nocturnal Ltpidojitera, to which belongs 

 the common Magpie Moth, A. yrosttilnriata. The caterpillar of this 

 moth attacks the leaves of gooseberry and currant bushes at the 

 beginning of the summer. It is of a yellowish white colour, with an 

 orange stripe on each side, and covered with black spots. The 

 chrysalis is black, relieved at its pointed end with orange circles. 

 The expanded fore-wings of the perfect insect measure about one inch 

 and a half across. The wings are of a yellowish white colour, variously 

 spotted with black. The fore-wings have a baud of pale orange. The 

 body is orange, spotted with black. The eggs are deposited on currant 

 or gooseberry leaves in July or August, and the caterpillars are hatched 

 in September. To get rid of the attacks of these creatures, they may 

 be picked off, or dusted with the powder of white hellebore, or the 

 leaves of the plants attacked may be burned. 



ABHAXITK (Zetigonite, Gismondine}, a mineral belonging to the 

 group of aluminous hydrated silicates, with alkaline and lime bases. 

 It contains, besides silica and water, about 26 per cent, of alumina, 

 with 14 per cent, of lime and potash. 



AHROCOMA. [HABROCOMA.] 



AliROMA (from a and Ppu^a, 'not fit for food," in opposition to 

 Tlii'<i>n-"iii'i. 'food for gods'), a genus of plants belonging to the 

 natural order Byttntriacece. The species consist of small trees, with 

 hairy lolied leaves and extra-axillary or terminal few-flowered 

 peduncles at the tops of the branches. 



Ah, > is a handsome tree, with drooping purple flowers, 



seated on peduncles opposite the leaves. It is a native of the East 

 Indies. The fibrous tissue of the bark of this plant is manufactured 



Hit" r.inlMg.'. 



ABRUS (from aBfts, soft), a genus of plants belonging to the 

 papilionaceous division of the order Ltyuminotce. The calyx is 

 bluntly 4-lobed, with the upper lobe broadest. The legume is 

 oblong, compressed, and 4-6-seeded. There is but one species, A. 

 which is a delicate twining shrub, with abruptly pinnate 

 li-iivi'H, bearing many pairs of leaflets. It is a native of the East 

 Indies, but is also found in the tropical parts of Africa and America, 

 where perhaps it has been introduced. The seeds of the commoner 

 y are red, with a black spot, whilst other varieties produce 

 various coloured seedg. These seeds are in much request as ornaments 

 amongst the inhabitants of the countries where they grow. They are 

 utmiiif as beads, with shells, and other hard seeds. They are brought 

 to Knrope from Guinea and the East and West Indies. They are used 

 frequently as beads for rosaries ; hence the name precatorius given to 

 thin species. The leaves and roots of this plant secrete the sweet 

 nee which characterises the liquorice plant (dhii //////; r/labra). 

 In the West Indies it is called Wild Liquorice, and used for the same 

 purposed as the common liquorice. The seeds have been accused of 

 possessing narcotic properties, but this is an error. When swallowed 

 they are verv indif 'Ht.iMf. 



ABSORBENT SYSTEM. The delicate vessels which in the bodies 

 of vertebrate animals are engaged in carrying the food and other 

 matters into the circulation, have this name. It consists of two 

 principal divisions, which may be regarded as two different sets, 

 given off from a common stem. One of these takes its origin in the 

 walla of the alimentary canal, more especially the small intestines, and 

 'lacteal ' system, from the white colour of the liquid it 

 takes up ; whilst the other commences in the substance of the body, 

 more especially the skin and neighbouring part*, and is called the 

 ' lyrnph;it,ic ' system, from the colourless fluid, called lymph, which it 

 carries. 



The Isirtrnlt are the small system of vessels l.y which the chyle, or 



KAT. II1HT. DIV. VOL. I. 



nutritive part of the food, is conveyed from the intestines to the left 

 subclavian vein, in which it is mixed with the blood. They have their 

 origin in the villi of the small intestines, which are short hair-like 

 processes, each consisting of a fine uet-work of lacteal vessels sur- 

 rounded by capillary arteries and veins. On the outside the villi are 

 covered with cells, which absorb the chyle before it is conveyed to the 

 loops of the lacteals in the interior of the villus. From the villi the 

 chyle is carried, between the layers of the mesentery, through 

 numberless converging branches, to the thoracic duct, the main trunk 

 of the absorbent system, which, at the part where the chief lacteal 

 branches join it, is dilated into what is called the Receptaculum Chyli. 

 The villi have no visible apertures for the entrance of the chyle, but 

 the walls of the lacteal vessels themselves are extremely thin and 

 permeable, and their canals are furnished with numerous and delicate 

 valves, like those of the veins [CIRCULATION OF THE BLOOD], to 

 prevent the fluid which they contain from descending again to 

 their absorbing extremities. In their passage through the mesentery 

 the lacteals traverse numerous mesenteric absorbent glands, where 

 they communicate with veins, and the fluid contained in them 

 is exposed to the influence of the blood, from which it acquires 

 colouring matter and fibrine. 



The Lymphatics consist of minute branched tubes of extremely 

 delicate membrane, whose extremities are arranged in a more or less 

 dense net-work in every part of the body. From this net-work they 

 gradually converge into a succession of branches of increasing size, and 

 terminate in two main trunks, called the right and left great Lymphatic 

 Veins, through which the lymph is poured with the chyle from the 

 thoracic duct into the right and left subclavian veins. The lymphatics 

 also communicate with the veins at some other parts of their course, 

 chiefly near their minute extremities, and more rarely by larger 

 branches. They have in their interior numerous delicate valves formed 

 of crescentic folds of the lining membrane, like those of the veins and 

 of the lacteals [CIRCULATION OF THE BLOOD], and, like them, pre- 

 venting the retrograde course of the contained fluid. The valves of 

 the lymphatics, however, are much more closely set than those of the 

 veins, so that, when full of fluid, the spaces between them being most 

 distended, they give those vessels a knotted or bearded appearance, by 

 which they are easily distinguished from veins of the same size. In 

 the course of the larger lymphatics there are numerous glands of the 

 same nature as those found in the course of the lacteals. They are 

 called Lymphatic Glands. To each of these there pass two or more 

 lymphatic vessels, which on entering them become extremely tortuous, 

 and after varied convolutions and anastomoses, terminate in nearly the 

 same number of branches, which again pass from the gland, and pursue 

 their course towards the main trunk. These glands attain their fullest 

 development in man and the mammalia. They are far less numerous 

 in birds, and are entirely wanting in the fish and amphibia. The 

 function performed by these glands is somewhat obscure, but it has 

 been recently suggested by Professor Bennett, of Edinburgh, that their 

 function is to prepare or produce the colourless corpuscles of the 

 blood. [BLOOD.] He arrives at this conclusion from having observed 

 that in cases where these glands or the spleen are inflamed, or in a 

 condition of increased action, that the colourless corpuscles of the 

 blood can be seen under the microscope to be in larger quantity than 

 is normal. (Bennett, On Leucorythemia.) 



ABSORPTION, one of the first and most essential of the functions 

 of animal and vegetable tissues. Both animals and plants grow and 

 perform other vital functions through the ngency of materials derived 

 from without. The passage of all substances from the exterior to the 

 interior of their bodies is effected by the function of absoqrtion. 

 This function ia performed in all cases by the aid of animal or 

 vegetable, membrane. This membrane is always in the form of the 

 walls of cells or the walls of vessels formed out of cells. Whether the 

 function of absorption be performed in animals or plants, there are 

 certain general conditions of the membrane or cells through which it 

 takes place, that are necessary in all cases. In the first place, as 

 liquids are found to pass through the walls of cells and membranes, 

 it is necessary that they should be permeable. This is found to be 

 the case in all organised bodies, and in proportion to the permea- 

 bility of the tissue is the activity with which absorption is performed. 

 In certain parts of plants, as well as animals, the cells become almost 

 impermeable, and these are the parts which cease to grow or to perform 

 active functions. Such are the duramen or heart-wood of trees, and 

 the nails, hairs, horns, and teeth of animal bodies. 



During the performance of the various functions in which absorption 

 is required, both liquids and gases pass through the cell-membrane 

 or cell-wall. Liquids containing salts in solution pass into the plant 

 and animal in the supply of food for nutrition. Gases, including the 

 vapour of water, are also absorbed by the cells of plants as a nutritive 

 process, and by those of animals during the performance of the 

 respiratory function. This transmission of fluids through organic 

 membranes is sometimes referred to as a peculiar vital property of 

 animal and vegetable tissues; but it seems to depend considerably on 

 the physical properties of the fluids and tissues. Organic membranes, 

 when separated from the living structure, have the power of absorbing 

 fluids, and if two fluids of different densities are separated by a mem- 

 brane, the flow through the membrane will be greater from the thinner 

 fluid to the thicker than the contrary. This action, which has been 



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