Page:Encyclopædia Britannica, Ninth Edition, v. 2.djvu/802

736 of them, such as Aster speddbilis of North America, aro very showy. The plant called the Cape Aster is Agathcea amelloides, while the China aster is Callistephus cfiinensis. Both these plants belong also to the Natural Order Composites. A variety of the Chinese aster, having beautifully coloured florets of rose, violet, and white, is called Heine Marguerite by gardeners.  ASTERIUS, of Cappadocia, was a heathen sophist and teacher of rhetoric in Galatia. About the year 300 he was converted to Christianity, and became the disciple of Lucian, the founder of the school of Antioch. During the persecution in 304 he relapsed into Paganism, but was received again into the church by Lucian. He is best known as an able defender of the Arian doctrine, and was styled by Athanasius the &quot; advocate &quot; of the Arians. His chief work was the Syntagma, but he wrote many others, chiefly commentaries. Cf. Mountfaucon, Collectio Nova PP. et Script. Graze.  ASTERIUS, Bishop of Amasia, in Pontus, in the end of the 4th and in the beginning of the 5th century. His fame rests chiefly on his Homilies, which were greatly esteemed in the Eastern Church. Most of these have been lost, but five were published in a 4to vol. by Ph. Rubenius of Antwerp in 1615, under the title Aster ii Amos. Ilomil. Quinque, Gr. et Lat. Combefis published six more, so that we have eleven complete ; and Dupin gives fragments of at least twenty-two.  ASTEROIDS, the name given to a large number of small planets, which revolve round the sun in orbits lying between those of Mars and Jupiter. They are all extremely small, their brightness seldom exceeding that of stars of the eighth magnitude ; their paths, which cross and recross each other, extend over a belt about 250,000,000 miles in breadth ; and the eccentricities of the orbits of many of them, and the inclinations of their planes to the plane of the ecliptic, are much greater than those of the larger planets. All the asteroids have been discovered during the present century. The first seen, Ceres, was discovered by Piazzi at Palermo on the first day of the century (Jan. 1, 1801), Pallas was seen in 1802, Juno in 1804, and Vesta in 1807. The next, Astraea, was not discovered till 1845 ; three more were seen in 1847, and since that time the number has been increased every year, amounting at the end of 1874 to 140. (See, p. 806.)  ASTHMA ([ Greek ], a gasping, [ Greek ], to gasp for breath), a disorder of respiration characterised by severe paroxysms of difficult breathing, usually followed by a period of complete relief, with recurrence of the attacks at more or less frequent intervals. The term is often incor rectly employed in reference to states of embarrassed respiration, which are plainly due to permanent organic disease within the chest, and which have none of the distinctive characters of true asthma. The onset of an attack of asthma is usually sudden, although there may exist certain premonitory symptoms which warn the sufferer of its approach, such as a feeling of discomfort, drowsiness, irritability, and depression of spirits. The period when the asthmatic paroxysm comes on is generally during the night, or rather in the early hours of morning. The patient then awakes in a state of great anxiety and alarm, with a sense of weight and tightness across the chest, which he feels himself unable to expand with freedom. Respira tion is performed with great difficulty, and is accompanied with wheezing noises. His distress rapidly increases, and he can no longer retain the recumbent position, but gets up, and sits or stands with his shoulders raised, his head thrown back, and his whole body heaving with his desperate efforts to breathe. His countenance is pale or livid, and wet with perspiration, while his extremities are cold ; his pulse is rapid and weak, and frequently irregular or intermitting. All his clothing must be loose about him ; he cannot bear to be touched, and the very presence of others around him seems to aggravate his distress. His one desire is to breathe fresh air ; and he will place himself by an open window and sit for hours in the middle of the night, unmindful of the exposure. His appearance is alarming in the extreme, and it often seems as if each breath would be his last. The paroxysm, after continuing for a variable length of time, often extending over many hours, begins to abate, the breathing becomes easier, and the subsidence of the attack is frequently marked by the occurrence of coughing with expectoration. When the expectoration is abundant the asthma is called humid, but where there is a little or none it is termed dry. After the cessation of the attack the patient appears to be and feels comparatively well. In cases, however, of long standing the subject of asthma comes to bear permanent evidence of its effects. He is easily put out of breath on exertion and he requires to lie with his head elevated, circumstances to be ascribed to organic changes in the chest, which oft- recurring attacks of asthma are liable to induce. The asthmatic paroxysms, although occasionally periodic, do not generally observe any regularity in their return. They may recur each successive night for several days, or there may be no return for many weeks or months, this being to a large extent dependent on a renewal of the exciting caise. Asthma is much more common in men than in women. In may be developed at any age, but is most fre quently observed in early and middle life. A large number of cases take their origin in diseases affecting the respiratory system during infancy, such as hooping-cough, measles, and bronchitis. Asthma is often hereditary, and in all cases one attack appears to predispose to others. With respect to the pathology of asthma, it is now gene rally held that the essential nature of the disease consists in a spasmodic contraction of the bronchial tubes. This is due to some deranged condition of the nervous system, affecting, either directly or by reflex action, the nerves supplying the contractile fibres lining the bronchi and regulating their calibre. The bronchial tubes being thus spasmodically narrowed, and losing for the time their expansile power, air can only, with the utmost difficulty, be got into or out of the chest. In these circumstances the muscles of the trunk concerned in respiration are called on to act with great violence to expand the chest, but witk little avail, and hence the distress and threatened suffoca tion. But while asthma is thus to be regarded as essentially a nervous ailment, its occurrence, apart from some organic disease in the chest or elsewhere, is admitted to be com paratively rare. Some cases, however, appear to be of purely nervous origin. To these the term Nervous or Spasmodic Asthma is applied, and it is more particularly to this form that the symptoms above narrated refer. In such cases no actual disease can be discovered with which the asthma could be directly connected. Attacks of this nature appear capable of being excited in those subject to them in very various ways. Thus violent emotions are not unfrequently the cause of asthmatic paroxysms. The effect of the inhalation of certain effluvia in exciting attacks of asthma is undoubted, as in the familiar instances of the odour of hay and of ipecacuan. In no particular is the eccentric character of this disease more remarkable than iu that of locality. Changes of air, otherwise inappreciable, may give occasion to the most severe attacks of asthma, as, on the other hand, they may be the means of accomplishing a cure of the disease where it exists. Circumstances, ap parently the most trifling, have been known to give rise to severe paroxysms of asthma, as the extinguishing of a light in a sleeping apartment or the shutting of a door. But asthma is very frequently associated with some form 