Page:The American Cyclopædia (1879) Volume VI.djvu/88

 80 DIAS undergoing, the bowels are irritable, and diar- rhoea often supervenes; this is best guarded against by care in the diet and a proper ob- servance of hygienic regulations. A popular remedy for diarrhoea, especially in cases which precede an attack of cholera, is a mixture of equal parts of laudanum, tincture of rhubarb, spirits of camphor, tincture of capsicum, and essence of peppermint, taken in doses of 20 to 80 drops in a little water at frequent intervals until relief is afforded. (See CHOLERA.) DIAS, A. Gonfalm, a Brazilian poet, born in Caxias, Aug. 10, 1823, died at sea in 1864. He was educated in Portugal, and returning to his native country published a volume of poems entitled Primeiros cantos (Rio de Ja- neiro, 1846), which was followed by his drama of Leonor de Mendonca, Segundos cantos, and Ultimo* cantos. In 1848 he was chosen pro- fessor of national history in the college of Dora Pedro II. In 1855 he was sent by the government to study the scientific institutions of France and Germany. Returning to Brazil in 1858, he was appointed historian and eth- nographer to the expedition sent by the govern- ment to explore the provinces bordering on the Amazon. In consequence of his arduous labors in this expedition he visited Europe in 1862 to restore his health. In September, 1864, he embarked for Brazil, and died near the coast. Dias published the first four can- tos of an American epic, Os Tytribiras (Leipsic, 1857), and a Diccionario da lingua Tupy, cJia- mada lingua 'brasiliana (Leipsic, 1858). A collection of his poems, under the title Cantos, was published at Leipsic (4th ed., 1865). His poetry is popular in Brazil. DIAS, Bartholomeu, a Portuguese navigator, born about the middle of the 15th century, lost at sea, May 29, 1500, while on his way from Brazil to India. In 1486 he sailed on an ex- pedition to explore the W. coast of Africa, and without knowing it was carried around the southern point of the continent and landed at the mouth of Great Fish river, where he dis- covered that he was on the E. coast. The stormy cape, which he doubled on his return in 1487, he called Cdbo Tormentoso, a name which the king of Portugal changed into Cabo de Boa Espernnca or Cape of Good Hope. He subsequently sailed on another African expedi- tion under Vasco da Gama ; and he command- ed one of the vessels in the fleet with which Cabral discovered Brazil. It was on this ex- pedition that he perished. IM STASE (Gr. dilarrip, to separate), a pecu- liar principle which is formed during the ger- mination of seeds. It is most abundantly pro- duced in the cereals, particularly in barley. It is formed at the base of the sprout, by a change which takes place in the albumen within and about the germ by the action of the vitalizing principle which has been awakened within it by heat and moisture. For the mode of pre- facing diastase, see BREWING. It may be ex- tracted from malt by steeping in water at DIATHERMANCY about 80 F., when it will be dissolved together with an albuminous body. A pasty mixture is produced, which is pressed, and the liquor fil- tered and heated to about 170, to coagulate the albuminous body, and again filtered. This filtrate contains the diastase, and may be used for obtaining the peculiar effects of that body ; but to obtain it in a pure state it is precipitated from the solution by the action of absolute al- cohol. It is a white, amorphous, flocculent substance, soluble in water and dilute alcohol, but insoluble in absolute alcohol, tasteless, and easily decomposed. Moistened starch, when subjected to the action of only a minute quan- tity of it (one part in 2,000, according to Pay en and Persoz), at 150 F., soon becomes disorgan- ized and converted into soluble starch, dex- trine, and grape sugar. Diastase in solution changes so readily that it soon becomes acid and loses its power of transforming starch. It is destroyed by boiling its solution; an im- portant fact, which is taken advantage of in the manufacture of dextrine, to arrest the transformation when the production of that substance has reached the greatest practicable amount, and also in the brewing of beer, for the purpose of preventing fermentation during the cooling of the wort. It has never obtained in such a condition as to afford i isfactory analysis. According to the above authorities, the amount of nitrogen varies being less when the substance has been care fully prepared. From this fact, and from th( convertibility of starch into glucose by eral other substances, it has been sugge that instead of being a principle of defini composition, it is probably an albuminous com- pound, passing through a change or series of changes. This view is strengthened by the discovery, by Dubrunfaut, of another substance in malt, similar in its effects, which he has called maltine, and finds to be even more ac- tive than diastase; an equal quantity being capable of effecting ten times as much trans- formation. He also obtained a third but less active substance than diastase, and believes the latter and the other two substances to be the same body undergoing decomposition. The action of alcohol when used to precipitate the diastase destroys the so-called modifications. DIATHERMANCY (Gr. 6t&, through, and etp/ia, heat), permeability to the rays of heat. Dia- thermanous bodies have the same relation to calorific rays that transparent ones have to rays of light ; and those bodies which are im- permeable to rays of heat, or bear the same relation to it that opaque ones do to light, are called athermanous. It was long known that rays of heat from an intense source were ca- pable of passing through certain transparent substances, like glass, in lines subject to the same laws of refraction as those of light ; but it was not supposed that such transmission was possible through bodies which are opaque to light. Pictet of Geneva was the first to show that radiant heat, from obscure as well as from