ASBESTOS AS CLEPIADE.E, 



211 



bell-shaped, limb three-cleft, erect or revolute; sta- 

 mens situate on the germen ; filaments awl-shaped, 

 anthers fixed below the apex of the filaments, two- 

 celled ; style thick, short ; stigma six-lobed ; capsule 

 leathery, six-celled ; seeds covered with a glandular 

 sul istance, which, when off, shows a semilunar spot. 

 This plant is said to grow wild at Rochdale, in 

 Lancashire. 



ASBESTOS, or AMIANTHUS, a mineral which 

 derives its latter name from a Greek word signifying 

 nnxtainc.il. This was given to it by the early minera- 

 logists from its power of passing through fire without 

 soil or stain. 



Flexible asbestos is of a whitish colour, approach- 

 ing to green, but in some few cases of a bright red. 

 It occurs in veins in serpentine at St. Keven, in 

 Cornwall ; and is found in a number of places in 

 Scotland, especially in veins of micaceous slate at 

 Glenelg in Inverness-shire. On the continent of 

 Europe it is found in the Hartz, in veins of primitive 

 greenstone ; in Bohemia, in metalliferous beds, along 

 with magnetic ironstone ; in Upper Saxony, in veins 

 of serpentine ; and in a similar situation in Silesia 

 and Switzerland. In Dauphiny, and on the St. Go- 

 tluird, it is found in contemporaneous veins in gneiss 

 and mica slate. Uncommonly beautiful white and 

 long fibrous varieties are met with in the Val de Scrre 

 in Savoy, at Cogne in Piedmont, and in the island 

 of Corsica. The mineralogist may also readily 

 supply his cabinet with specimens from the Uralian 

 mountains, and from several places, in the United 

 States of America. 



Flexible asbestos was employed by the ancients to 

 form a species of incombustible cloth ; in which the 

 remains of persons of distinction were consumed on 

 the funeral pile. The cloth was afterwards with- 

 drawn from the fire and inclosed with the ashes in an 

 urn ; and it is a curious fact that there now exists in 

 I he Vatican an asbestos shroud, containing ashes and 

 burnt bones several thousand years old. The value 

 of the asbestos mainly depends on the length of its 

 fibres, and also on its whiteness and flexibility. In 

 preparing the cloth, the asbestos is first carefully 

 washed to free it from all impurities ; and its fibres 

 then laid straight and interwoven with flax. The 

 t'tlirie is then passed through a furnace, by which the 

 flax and oil used in the operation of weaving are 

 consumed, and the process is completed. The 

 natives of Siberia weave gloves, caps, and purses of 

 asbestos ; and it is formed into girdles, ribands, and 

 other articles, in the Pyrenees. 



Asbestos is a very slow conductor of heat ; and the 

 editor of the present work was presented by the 

 Chevalier Aldini with a glove of this mineral, in 

 which the hand was so perfectly protected from the 

 action of fire, that a bar of glowing hot iron might be 

 grasped, and held for some minutes without the 

 slightest inconvenience. This property has sug- 

 gested the employment of an entire dress for the use 

 of firemen. It has also been employed for an incom- 

 bustible wick to a spirit lamp. 



The common asbestos is darker in its colour than 

 the preceding. It occurs massive, and in distinct 

 fibrous concretions. When acted on by the blow 

 pipe it fuses very readily into a slight greyish 

 globule, similar to enamel. This mineral is found in 

 serpentine and in primitive greenstone ; it also occurs 

 in metalliferous beds along with ironstone as well as 

 with copper-ore. It is found, though but rarely, in 



Asia, and the United States of America. See ROCK 

 CORK, and ROCK WOOD. 



ASCARIS (Lamouroux). A genus of intestinal 

 worms, of the order Nematuides, Rudolph!. Cuvier, 

 having for its character, body cylindrical, attenuated 

 at both extremities, the mouth surrounded or pre- 

 ceded by three tubercles. This genus is very nu- 

 merous, and the animals which compose it are easily 

 distinguished from all others, although the species 

 are often confounded with each other. They ap- 

 pear to acquire their full growth in a very short 

 time ; some are scarcely half a line in length, while 

 others attain a considerable size. 



These worms are very common ; some animals nou- 

 rish many species, some of them in great numbers ; 

 others are solitary or rare, and we only observe them 

 in certain seasons. The greater part of these animals 

 are found in the intestinal canal ; others in the interior 

 of the lungs, and various other parts of the body. 



There are nearly five hundred species described ; 

 about two-thirds are certain, ' the others still doubtful. 

 It is probable that many remain undescribed, and in 

 many instances the same species has been described 

 under different 'names, in consequence of their ap- 

 pearance at different stages of their existence. The 

 more remarkable species are the A. lumbricoides, Lin- 

 naeus, which is sometimes found twelve inches long. 

 It is found in the intestines of the human body, the 

 ox, the hog, the horse, and the ass ; they sometimes 

 increase so much as to cause serious illness in children. 

 The A. mystax, Rudolphi, is found to inhabit the in- 

 testines of cats, both in a savage and domestic state. 

 The A. maculosa, Rudolphi, is found in the domestic 

 pigeon and the turtle dove. The A. echmata, Rudol- 

 phi, is a very singular species ; the head presents 

 three great tubercles ; the body is attenuated behind, 

 and terminated by a tail, long, very slender, turned up 

 at the extremity, and all the surface presents a number 

 of little needles (aigtdllom) directed backwards, si- 

 tuated in transverse ranges. It lives in the intestines 

 of the gecko. 



ASCLEPIADE^E. A natural family of dicoty- 

 ledonous plants, containing between forty and fifty 

 genera, and upwards of two hundred and sixty 

 species. They are closely allied to the apocyneae, 

 but differ from them in having the stamens united 

 together so as to form one body, and the pollen 

 coherent in masses of a waxy substance to the five 

 corners of the flat central stigma. The essential 

 botanical characters are in other respects so similar 

 to those of the apocynese already detailed, that it is 

 needless to enumerate them. The plants included in 

 this order are generally shrubby, but occasionally her- 

 baceous, and sometimes climbing. They are found 

 abundantly in Southern Africa, India, New Holland, 

 and the warm regions of America, more rarely in 

 temperate climates. Some of the succulent genera 

 inhabit the dry sterile plains of the African continent. 



In their general properties also the asclepiadeae 

 bear a close resemblance to the apocyneas. They 

 yield a milky juice, which is acrid, bitter, stimulating, 

 and sometimes poisonous. Many of them are used in 

 medicine, and some are employed as articles of diet. 

 The properties of the order will be best shown by 

 adducing a few examples. The asclepias, one of the 

 genera of this order, furnishes numerous species 

 which are said to be confined to the eastern side of 

 North America. This genus gives origin to the name 

 of the order, and is valued for the beauty and hardi- 

 X2 



