Page:The New International Encyclopædia 1st ed. v. 09.djvu/372

* GXTANIDIW. 328 GUANO. former boinj; mothyl-guanidiii-acetic acid, the lat- ter an anhydride of kreatin. GUANIN, gwa'nin, C5H5N5O. A yellowish- white aniorphuus substance, which derives its name from its l)eing a constituent of guano. It also forms, however, the chief constituent of the excrement of spiders, has been found attached to the scales of fishes, and seems to be a normal constituent of the mammalian liver and pan- creas. 'ith regard to its occurrence in guano, as it has not been found in the recent excrement of sea-birds, there is every reason to believe that it is formed by slow oxidation ( from atmospheric action) of uric acid, much as uric acid can be made to yield urea and oxalic acid. In the pan- creas and liver it probably represents one of those transitory stages of disintegi-ated nitro- genous tissues which are finally excreted by the kidneys in the more liighly oxidized form of urea. Guanin may be best prepared from Peruvian guano, which is for this purpose finely powdered and boiled with lime until the filtrate becomes colorless ; the residue is then boiled with sodium- carbonate solution, the liquid is filtered and precipitated with acetic acid. To purify the guanin thus obtained., it is boiled with dilute hydrochloric acid, from which it is subsequently freed by the use of concentrated ammonia. Gua- nin is insoluble in w.iter. ether, alcohol, and am- monia. By the' action of oxidizing agents it is converted into guanidin, parabanic acid, and carbon dioxide. The presence of guanin may he analytically detected with the aid of concentrated solutions of potassium chromate and potassium ferrocyanide, the former reagent producing an orange-colored, the latter a yellowish-brown, crys- talline precipitate, in solutions of guanin. When treated with nitrous acid, guanin is transformed into xanthin. The chemical constitution of gua- nin has been determined by Eniil Fischer. GUANO, gva'n6 (Sp. guano, hiiano, from Peruvian huanu, dung). A name applied to the excrement it ious deposits of sea-fowl, such as pelicans, penguins, and gulls, which are found on certain coasts and islands where the climate is dry and the rainfall slight. The deposits some- times contain, in addition to excrementitious mat- ter, the remains of the birds themselves, as well as of seals, walruses, and various other animals. Although the use of guano as a manure is com- paratively recent, dating from about the middle of the nineteenth century, its value in agricul- ture was well known to the Peruvians long before they were visited by the Spaniards, probably as early as the twelfth century. Alexander von Humboldt first brought specimens of guano to Europe in 1S04, and had them examined by the best anah'tical chemists of the day. Since then numerous analyses have been reported. The most noted deposits of guano are those found in the vicinity of Peru ; but valuable beds have been discovered in many other parts of the world — viz. in North America. West Indies. Australia, Asia, Africa, and certain islands of the Pacific. The deposits, however, occur mainly within 10° to 20° north and south of the equator. The qual- ity and value of the guano commercially depend almost wholly upon the amount of decomposition to which it ha.s been subjected by the action of the atmosphere. The ficcal matter of the fish- eating birds, which by its long accumulation forms the guano deposits, consists essentially of nitrogenous and phosphatic compounds, the for- n'.er l)eing chiefly ammonia salts and nitrates de- rived from the decomposition of the uric acid and urates which exist in the fresh excrements of the birds, as well as of undeconiposed or partiallj' decomposed uric acid and urates and other or- ganic compounds. The annnoniacal salts and nitrates, and some of the phosphates, are soluble in water, and are readily washed away by rain. In dry climates, where very little rain falls, as in some parts of Bolivia and Peru, on the western coasts of South America, the deposit of excreta sutlers very little from the action of the atmos- phere, and retains nearly the whole of its nitro- genous and phosphatic compounds. Guanos, on the other hand, found in regions where rain falls free- ly, lose a great part of their soluble constituents, but remain rich in their less soluble constituents — the phosphates of lime and magnesia. Guanos ma.v, therefore, be divided, according to their composition, into three classes: (1) Those which have sutTered little from atmospheric action, and which retain nearly the whole of their original constituents, such as the Angamos and Peruvian guanos; (2) those which have lost a considerable portion of their soluble constituents, such as the Ichaboe, Bolivian, and Chilean guanos; (3) those which have lost nearly all their ammonia, and contain but little more than the earthy phosphates of the animal deposit. Many of these are large- ly contaminated with sand. In this class belong the African (excepting Ichaboe). West Indian, Kuria iluria. Sombrero, Patagonian, and Shark's Bay guanos. Aikman cla.sses guanos as nitrogenous and phos- phatic. and gives the following data as to the composition of the deposits which were reported as still being worked in 1894: C0.MPO8IT10N OP Guanos KIND or GCANO NITROGENOUS GUANOS Saldanha Bay Ichaboe Pahellon de Pica Piinta de Lobos Huaullloa , PHOSPHATIC GUANOS Baker Island Endei'bury .ve9 and Sidney Island Maiden Island Bro%'8e Island Huon Island Nitrogen Per cent. 9 8 7 4 6 Phosphoric acid 9 14 15 13 39 37 Si 32 3L 28 Of the more important deposits of nitrogenous guanos which have been exhausted, Angamos con- tained nitrogen 20 per cent., phosphoric acid 5 iier cent. : Chincha. nitrogen 14 per cent., pho.s- phoric acid 1.3 per cent. : Ballcstas, 12 per cent, each of nitrogen and phosphoric acid : Macabi, nitrogen 11 per cent., phosphoric acid 12 per cent. : Corcovao, nitrogen 1 1 per cent., phos- phoric acid 1.5: Independence Bay. nitrogen 7 per cent., phosphoric acid 12. Among the phos- phatic deposits now exhausted, but of historical interest, were Maraeaibo, or Jlonks, with 42 per cent, of phosphoric acid ; Raza Island and Cura- cao, 40 per cent. : Starbuck. 38 per cent. ; Fan- ning Island and Howland, 34 per cent.; Mejil-