Asr.KSTUS. 



ASCLKI'IAS. 



from the violence of it* effects, it U now properly laid aside in medical 

 practice : it ii xtill however used in veterinary medicine, to vomit and 

 purge. The fine powder applied to the nostril* causes sneezing, and 

 a flow of mucus from the membrane which line* those parts. It U 

 therefore extensively employed aa an en-bine, and U the basis or chief 

 ingredient of many cephalic snuff*. It is used in chronic inflamma- 

 tions and some other diseases of the eye, and in headache*. Win T.- 

 theee last arise from disorders of the digestive function, such means 

 can be of no avail: where they are connected with congestion < 

 fullness of the vessels of the bead, the increased discharge from the 

 Schneiderian membrane may give temporary relief in the same way 

 as a few drops of blood flowing spontaneously from the none, or 

 obtained by puncturing the membrane. When taken into the stomach 

 in considerable quantity, it acts as a poison. 



ASBESTUS must be considered, in Mineralogy, rather as a term 

 implying a peculiar form sometimes assumed by several minerals, than 

 as a name denoting a particular species ; it is in fact applied to varie- 

 ties of the Amphibolic Minerals, such as Actinolite, Tnmulite, &c., 

 which occur in long capillary crystals, placed side by side in parallel 

 position, and thus giving rise to a fibrous mass. As might be expected, 

 the above conditions are fulfilled in various degrees, and there are 

 accordingly various kinds of Asbestus. Those varieties, the fibres of 

 which are very delicate and regularly arranged, are called Amianthut,a 

 Greek term signifying unpolluted, unstained. The individual crystals 

 are here readily separated from each other, are very flexible and 

 elastic, and have a white or greenish colour with a fine silky lustre. 

 Though a single fibre is readily fused into a white enamel, in mass it 

 is capable of resisting the ordinary flame, so that when woven it pro- 

 duces a fire-proof cloth, and hence the name from the Greek (urffiaro!, 

 in the sense of indestructible. The most beaiitiful specimens have 

 been found in the Tarentaiae in Savoy ; but Corsica must be consi- 

 dered as its principal locality, from its great abundance. It is also 

 found in Cornwall, at St. Neverne ; likewise in several ports of Scot- 

 land. It occurs also in the United States of America, where it is 

 sometimes used as a wick for an oil-lamp. 



Those varieties in which the crystals are coarser, with scarcely any 

 flexibility, are called Common Asbestus. It is generally of a dull 

 green, and sometimes a pearly lustre, and readily fuses before the 

 lili>w-pipe flame. It occurs more frequently than amianthus, and in 

 usually found in veins traversing serpentine. 



'I'll, -re are three other varieties, known by the names of Mountain 

 Feather, Mountain Wood, and Mountain Cork, which differ from the 

 Common Asbestus by the fibres interlacing each other. The two first 

 have received their names from their appearance ; the third from it 

 extreme lightness, and from its swimming in water. They have been 

 found in Scotland. 



ASCARIDES. [ENTOZOX] 



ASCI'DIA, a genus of Molluscous Animals belonging to Cuvier's 

 i.nl.-r of Act]ih(U<e without Shells. Savigny has considered these 

 animals sufficiently important to constitute a class under the name of 

 Aicalia (Atcidia) ; while Lamarck has also formed them with others 

 into a class under the name of Tuniciert (Tunicata). [TusicAT.v.] 



ASCLEPIADA'CE^E, Atclepiadi, a natural order of Exogenous 

 Plants, known from all others by the single character of its grains of 

 pollen adhering together within a sort of bag which occupies the 

 whole of the inside of each cell of the anther ; and when it falls out 

 sticks to glands of a peculiar character occupying the angles of the 

 stigma. Independently of this circumstance the anther and stigma 

 adhere firmly together, and the fruit is a very curious body, cm 

 of two carpels, which, when young, are parallel to each oth 

 united at the point; but when ripe are both on the same plane, [mint 

 ing in different directions, and shedding a large quantity of seed, the 

 ends of which terminate in long down. 



The most important and typical genus of this order is An ' 

 It consist* of shrubs or herbaceous plants, abounding in an acrid and 

 usually milky juice, and found in t Ip-ir greatest abundance in tn ipir.i I 

 countries, but rarely in cold latitudes. At the Cape of Good H| 

 they form a singular stunted deformed vegetation, in the form of the 

 leafless succulent stapelias, the flowers of which are among the most 

 fetid productions of the vegetable kingdom. A great many species 

 of Avlrjiiat inhabit North America, and for their beauty are fre- 

 ij'i'-mly cultivated in Europe, especially the orange-coloured AscUpiat 

 luberoM. Their roots are acrid and stimulating, and usually emetic. 

 Thrir flowers have curious horned processes added to the corolla. 

 [AacLcrus.] 



The roots of the whole order appear to bo acrid and stimulating, 

 and some of them, as Tylophorn atthmatica and Secamane emetica are 

 employed as emetic*. The Cow-Plant of Ceylon, or Kiriaghuiia 

 Plant (Gfmnema lattifcrum), yield* a milk which the Cingalese make 

 use of as food. Specie* of Cynanchnm act as purgatives. The leaves 

 <>f tnltniutrmmii Arijil are used in Egypt for adulterating senna. 

 Several specie* yield caoutchouc, whilst others afford indigo. 



(Liudlcy, VrgelMt Kingdom.) 



ASCLETIAS, a genus of plants, the type of the natural ",,], i 

 Aicltpuulatctr. Many of the specie* pones* powerful ui>-<li< iu.<l 

 qualities, and hence the name of the genus from ^Kwulap 

 (Asclepias), the god of medicine. The genus is characterised by 

 pomewiiig a reflexed 5-pnrted corolla ; n 5-lcared Corona seated on the 



Aiclrpiru Sprite** 



1, A flowering shoot; 2, n rinv\r tl" " fl " m 



above ; the centre in occupied by 



much magnified, a, one of the''' ->< of the corolla; 5, tin 



cut vertically, and lens nwmlied, n, one of tin- Imrm-il procrwcn ; i, pollen 

 miMrn. a, the gUnd ; 7, ono half of a ri|>c fruit ; 8, n transverse view of i( 

 Inside near the point, nhowlng how tbe ccd are arranged; 9, need; 10. 

 the same cut acrou ; 11, the iarac cut vertically, showing the embryo; 12, 

 the embryo neparate. 



