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 with the species of animal. In man, Burian and Schur state that one half of the total amount is so converted. Some workers, like Wiener, hold that uric acid may be synthesized in the body, but while this is undoubtedly so in the case of the bird, in the mammal it has not been definitely established. The other chief purin bodies present in urine are xanthin and hypoxanthin, purins less oxidized than uric acid; the first is a dioxypurin, and the second is a monoxypurin. The main source of total purin supply would seem to be muscle metabolism. The mother substances from which all are derived in the body are the nucleins. These complex bodies are apparently first broken down by enzyme action to aminopurins. These in their turn have their amino groups split off, and then, according to the degree of oxidation, the different purin bodies are formed.

Creatinin.—The physiological significance of this substance is as yet unknown. The daily excretion varies little with the character of the diet, provided, of course, that the diet be creatin creatinin free. It appears to be proportional to the muscular development and muscular activity of the individual. Hence it would seem to be derived from the creatin of muscle, a substance which is very readily changed into creatinin outside the body. In the body the conversion of creatin into creatinin seems to be strictly limited and hence when creatin is taken in flesh in the food it tends to appear as such in the urine. It would seem that it is either in great part decomposed in the body into what we do not at present know or that, as suggested by Folin, it may be used as a specialized food. Whatever its source, after urea and ammonia it is one of the most important nitrogenous substances excreted, the daily excretion being about 1·5 grms.

The sulphur excreted in the urine comes chiefly from the sulphur of the protein molecule. It is excreted in various forms. (1) As the ordinary preformed sulphates, that is, sulphur in the form of sulphuric acid combined with the ordinary bases. (2) As ethereal sulphates, that is, in combination with various aromatic substances like phenol, indol, &c. (3) In the form of so-called neutral sulphur in such substances as cystin, which are intermediate products in the complete oxidation of sulphur.

Phosphorus appears linked to the alkalis and alkaline earths as phosphoric acid. A very small part of the phosphoric acid may be eliminated in organic combination such as the glycero-phosphates, &c.

Sodium (mostly as sodium chloride), potassium, calcium and magnesium are the common bases present in the urine. The lungs are the important channel of excretion for the waste product of carbon metabolism CO2 (see ); and also a very important channel for the excretion of water. As regards the skin, the sweat carries off a large amount of the water, but it is difficult to determine the total amount. It has been estimated that about 500 c.c. is excreted per diem under normal conditions. Sweat contains salts, chiefly sodium chloride, and organic waste products. Of the organic solids excreted from this source urea forms the most important under normal conditions. Under pathological conditions, especially when there is interference with free renal action, the amount of nitrogenous waste excreted may become quite important. There is also a small amount of CO2 excreted by this channel.

NUTTALL, THOMAS (1786–1859), English botanist and ornithologist, who lived and worked in America from 1808 until 1842, was born at Settle in Yorkshire on the 5th of January 1786, and spent some years as a journeyman printer in England. Soon after going to the United States he was induced by Professor B. S. Barton (1766–1815) to apply himself to the study of the plants of that country. In 1825–1834 he was curator of the botanic gardens of Harvard university. In 1834 he crossed the continent to the Pacific Ocean, and visited the Hawaiian Islands. Some property having been left him in England on condition of his residing on it during part of each year, he left America in 1842, and did not again revisit it except for a short time in 1852. He died at St Helens, Lancashire, on the 10th of September 1859.

NUWARA ELIYA, a town and sanatorium of Ceylon. Pop. (1901) 5026, with 1000 additional visitors during the season. It is situated 6240 ft. above sea-level, with the highest mountain in the island, Pedrotallagalla, towering over the plain for 2056 ft. more. Nuwara Eliya is reached from Colombo by railway, eight hours to Namuoya, and thence, by a light 2-ft.-gauge line, running up to the heart of the sanatorium. The average shade temperature for the year is 58° F.; the rainfall, 95 in. Considerable sums have been spent by the government in improving the place.

NUX VOMICA, a poisonous drug, consisting of the seed of Strychnos Nux-Vomica, a tree belonging to the natural order Loganiaceae, indigenous to most parts of India, and found also in Burma, Siam, Cochin China and northern Australia. The tree is of moderate size with a short, thick, often crooked, stem, and ovate entire leaves, marked with three to five veins radiating from the base of the leaf. The flowers are small, greenish-white and tubular, and are arranged in terminal corymbs. The fruit is of the size of a small orange, and has a thin hard shell, enclosing a bitter, gelatinous white pulp, in which from 1 to 5 seeds are vertically embedded. The seed is disk-shaped, rather less than 1 in. in diameter, and about in. in thickness, slightly depressed towards the centre, and in some varieties furnished with an acute keel-like ridge at the margin. The external surface of the seed is of a greyish-green colour and satiny appearance, due to a coating of appressed silky hairs. The interior of the seed consists chiefly of horny albumen, which is easily divided along its outer edge into halves by a fissure, in which lies the embryo. The latter is about in. long, and has a pair of heart-shaped membranous cotyledons.

The chief constituents of the seeds are the alkaloids (q.v.) and brucine, the former averaging about 0·4%, and the latter about half this amount. The seeds also contain an acid, strychnic or igasuric acid; a glucoside, loganin; sugar and fat. The dose of the seeds is 1 to 4 grains. The British Pharmacopoeia contains three preparations of nux vomica. The liquid extract is standardized to contain 1·5% of strychnine; the extract is standardized to contain 5%; and the tincture, which is the most widely used, is standardized to contain 0·25%.

NYACK, a village of Rockland county, New York, U.S.A., in the town of Orangetown, on the western bank of the Hudson river, about 25 m. north of New York City. Pop. (1890) 4111; (1900) 4275, of whom 583 were foreign-born; (1905) 4441; (1910) 4619. Nyack is served by the Northern Railroad of New Jersey (a branch of the Erie), and is connected by ferry with Tarrytown, nearly opposite, on the eastern bank of the Hudson. The New York, Ontario & Western and the West Shore railways pass through West Nyack, a small village about 2 m. west. For about 2 m. above and 3 m. below Nyack the river expands into Tappan Zee or Bay, which is about 3 m. wide immediately opposite the village. The first grant of land within the present limits of Nyack was made by Governor Philip Carteret, of New Jersey, to one Claus Jansen, in 1671, but the permanent settlement apparently dates from about 1700. The adjacent villages of Upper Nyack, pop. (1905) 648, (1910) 591, and South Nyack, pop. (1910) 2068, form with Nyack practically one community. Nyack was named from a tribe of Algonquian Indians.

NYANZA (from the ancient Bantu root word anza, a river or lake), the Bantu name for any sheet or stream of water of considerable size; especially applied to the great lakes of east Central Africa. The word is variously spelt, and the form “Nyasa” has become the proper name of a particular lake. Nyanza is the spelling used in designating the great lakes which are the main reservoirs of the river Nile.

NYASA, the third in size of the great lakes of Central Africa, occupying the southern end of the great rift-valley system which traverses the eastern half of the equatorial region from north to south. Extending from 9° 29′ to 14° 25′ S., or through nearly 5° of latitude, the lake measures along its major axis, which is slightly inclined to the west of north, exactly 350 m., while the greatest breadth, which occurs near the middle of its length, between 11° 30′ and 12° 20′ S., is 45 m. In the northern and southern thirds of the length the breadth varies generally from 20 to 30 m., and the total area may be estimated at 11,000 sq. m.