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That when the oxygen and hydrogen are inthe exact proportions in which they constitutewater, the vegetable substance is analogous tosugar, gum, fecui::, ligneous fibre, &c.
'l'lie analysis of some of the primary animalsubstances was then undertaken. In this casethere is another element, azote, which requiresparticular notice. Whenever any animal mat-ter is deflagrated with an excess of oxymuriatof potash, a quantity of nitrous acid gas isformed, which, is the greatest where the heatrequired for combustion is the lowest. Thiscircumstance would render the analysis in theway above described much more complicatedand uncertain, unless some method could befound of preventing the formation of nitric acid.This the authors assert is effectually done bylowering the dose of the oxymuriat, so thatwith this, neither ammonia, nor nitric acidis produced, but the whole products are azoticgas, water, carbonic acid, and oxycarburettedhydrogen, and with proper precautions even thelatter compound may be almost entirely pre-vented, and nearly the whole of it changed tocarbonic acid and water. The requisite pro-portions of oxymuriat of potash and the animalmatter employed must be found by previoustrials with successive quantities. The animalmatter, long dried at 212°, must be mixedthoroughly, first with thrice its. weight of theoxymuriat and thrown into a crucible barelyred-hot. If the residue of the deflagration isblack it will shew that there is too little oxy-muriat, if it is white the quantity of this saltmay be too much, if it is greyish the proportionsare sufficiently correct; or at any rate neithernitric acid nor ammonia will be produced in thedeflagration, though perhaps there will be somecarburetted hydrogen. Whenever any gas con-tains along with this gas a certain proportion ofazote and carbonic acid gas, the presence ofthese will prevent the entire combustion of thecarburetted hydrogen with any oxvgen that maybe added. It will therefore be necessary to adda small quantity of pure hydrogen to producethe detonation of the carburetted hydrogen, andits total conversion into carbonic acid and water.
Fibrine . The iibrine collected from ox-blood by stirring it as soon as drawn, was driedby long exposure to boiling-water heat; and aportion of it calcined by itself left only T V offixed matter. Another portion was then mixedby long trituration with moist oxymuriat ofpotash, then made into balls and deflagrated inthe same manner as the vegetable substances.The flame was very intense, and much water
condensed in the cooler part of the apparatus.The -residue in the red-hot tube was a whitesaline mass consisting only of muriat of potashwith the incombustible part of the fibrine. Theresults' after subsequent analysis gave for theconstituents of fibrine, carbon, oxygen and hy-drogen in the proportions of water, some excessof hydrogen, and azote. The exact quantitieswill be found in the table.
Albumen from white of egg, Caseum or thepure cheese of milk, and Gelatine were ana-lyzed exactly in the same way, except that theoxymuriat was added to the gelatine in solution(its proportion of dry gelatine being known) andboth were dried together by boiling-water heat,this being the only way in which the two couldbe intimately mixed.
The general result of the analysis of thesefour animal substances is , that they all containeven more carbon than sugar or gum does, thatin all the hydrogen exceeds the proportion re-quired to form water with the oxygen pre-sent., and that the azote also found is not farfrom the proportion required to form ammoniawith the excess of hydrogen. Hence (sup-posing the small differences to arise from theunavoidable errors in the practical part of theexperiments) it is not unlikely that these animalsubstances might be resolved into carbon,water and ammonia. In this point of viewthese animal matters will bear a strong analogywith sugar, mucilage, &c. inasmuch as eachconsists of carbon, and other constituent parts inthe exact proportion in which they will uniteinto some definite compound, being carbon andwater in the vegetable substances ; and carbon,water, and ammonia in the animal.
The authors have not carried their experi-mental research further, hut they suggest theprobability of further analogies between thevegetable and animal principles in the animalacids and animal oils.
We shall not give the general observationswhich are suggested to the authors of these im-portant experiments, but shall only add thetables of the actual results. It will be under-stood that the substances analyzed are taken, ex-clusive of their incombustible earthy metallicand saline contents, and that no azote is consi-dered as entering into the vegetable principle.In the animal substances all the hydrogen andazote are estimated as constituting ammonia,allowing some excess or deficiency of this prin-ciple, to be attributable to accidental errors inthe experiments.
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