NEWS

liquid combination, enough water to hydrate the quick-blood which has circulated through a muscle in action is lime is incorporated by agitation, the temperature be- less than one-fourth of that contained in blood which has comes considerably raised, and in a few hours the entire traversed a muscle at rest, while there is a corresponding mass solidifies into a very homogenous pill-like consis- increase, not of course an equal increase, in the volume of tence. The proportion of water required is almost its carbonic acid; that the irritability of muscular fibre exactly a third of the lime employed. out of the body is arrested by its removal from oxygen, and again manifested on its re-exposure thereto; and lastly, that other things being equal, the amount of urea the lungs, is proportionate to the muscular activity of the excreted by the kidneys, and of carbonic acid excreted by individual. Seeing, then, that muscular exertion is really dependent upon muscular oxidation, we have to consider what should be the products, and what the value of its oxidation.

On repeating the previous experiment with ordinary calcined magnesia, M. Roussin established-1. That divers commercial balsams of copaiba contain a consider able proportion of water, which they will lose if exposed for a long time under a glass receiver, enclosing fragments of chloride of calcium or of carbonate of potash; 2. That the commercial calcined magnesia readily attracts the moisture of the air, and, after having been some time in a badly stopped vessel, always contains considerable quantities of water, sometimes to the extent of 15 and 20

per cent.

Unfortunately, the precise molecular formula-the exact chemical constitution-of muscle is at present unknown. But in muscle, as in all the albuminoid class of bodies, we do know the ratio in which the constituent carbon and nitrogen stand to one another. Thus it is established beyond all question that the ratio of the number of atoms of carbon to the number of the atoms of nitrogen in muscle is as nearly as possible, if not quite exactly, four to one. In the most minute fragment of muscle, then, for every single atomic proportion of nitrogen there are four atomic

If a specimen of good balsam of copaiba is divided into two equal parts, and having properly dried the first portion under a receiver, and sufficiently hydrated the other by placing it in a damp vessel, each portion is then mixed with one-sixteenth its weight of recently calcined magnesia, the dried portion remains liquid, and the mag-proportions of carbon, thus :nesia in great part even sinks to the bottom of the vessel, while the second portion, on the contrary, becomes a hard mass of pillular consistence.

The above facts show the necessity of the agency of water in order to bring about the combination of the resin of the balsam of copaiba with the lime and the magnesia. M. Roussin purposes to develope these results in a more extended investigation.

PROCEEDINGS OF SOCIETIES.

COLLEGE OF PHYSICIANS.

It will be more convenient, however, to express this ratio 4 CARBON to I NITROGEN.

four to one, we will adopt eight to two, as our expression by the doubles of the above numbers, so that, instead of of the atomic ratio of carbon to hydrogen in every particle of muscle:

8 CARBON to 2 NITROGEN. Admitting, as a result of its ultimate metamorphosis, that the whole of the nitrogen of muscle is converted into urea, let us first consider what proportion of its carbon of muscle must be associated with this nitrogen, and what proportion be left for excretion in the form of carbonic acid. Now, although the molecular constitution of muscle

"On Animal Chemistry." A course of Six Lectures by is undetermined, that of urea is perfectly definite.* WILLIAM ODLING, M.B., F.R.S., F.R.C.P.

Wednesday, May 10, 1865.
LECTURE 5.

As shown by its formula, CH NO, the molecule of urea consists of one atom of carbon, four atoms of hydrogen, two atoms of nitrogen, and one atom of oxygen. In other words, leaving out of consideration its hydrogen and

in urea have one atom of carbon associated with them; so as one to two. Accordingly, every two atoms of nitrogen that if we take the two proportions of nitrogen existing in muscle and add thereto the one proportion of carbon necessary to form urea, we shall have seven proportions of carbon left for conversion into carbonic acid, thus:

7-CARBON to

{2-NITROGEN.

of muscle is the appearance of one-eighth of its carbon in The theoretical result, then, of the complete oxidation the form of urea, and of seven-eighths of its carbon in the

Muscular action dependent on muscular metamorphosis-oxygen, the atomic ratio of carbon to nitrogen in urea is Theoretic oxidation of muscle into one proportion of urea and seven of carbonic acid-Practical results-Dynamic value of muscle oxidation-Quantities of heat producible by combustion of hydrogen and carbon-Difference between quantity and intensity of heat-Unit of heat equivalent to 430 kilogram-metres of motion Quantities of motion producible by combustion of hydrogen and carbon Economy of muscle as a motive exponent of combustionReciprocity of heat and motion in muscular action Muscular force traceable to the sun-Amount of force derivable from muscle proportional to degree of its oxidation-Imperfect knowledge of natural process of oxidation -Artificial oxidation of muscle-Nature of intermediate products-Relations of aldehydes and nitriles to acidsSimple constitution of acids obtained by muscle oxidation -Production of both fatty and aromatic compounds-fed Natural occurrence of leucine and tyrosine-Their formation by indirect oxidation of nitrogeneous tissue Leucine the most elaborate of fatty, and tyrosine of aromatic animal products- Constitution and analogies of leucine-Probable constitution of tyrosine-Its relation to hippuric acid.

THAT muscular exertion is dependent on muscular metamorphosis or oxidation is a subject rather for the physiologist than the chemist to dilate upon. Perhaps, however, I may be permitted to remind you of such observations as the following-that a free supply of thoroughly oxygenated arterial blood is essential for complete well-developed muscular action; that the volume of oxygen contained in

form of carbonic acid.

series of experiments made by Bischof and Voit, and Now, let us see what is the actual result. We have two Pettenkofer and Voit respectively, in which lean dogs were

exclusively upon a moderate diet of flesh. In the first series of experiments a small proportion of fat left in the experiments the fat was entirely removed. The general flesh was duly allowed for; while in the second series of results of these two series of experiments are shown

below:-
:-

C. of carb, acid.

C. of urea.

NEWS

Thus the ratio of carbon excreted in the form of carbonic acid to carbon excreted in the form of urea was as 729 to 1 in the first series of experiments, as 6'85 to 1 in the second series, and as 7'07 to 1 in the mean of the two. Theoretically, then, the ratio of carbon in carbonic acid to carbon in urea is as 7 to 1; experimentally it is found | to be as 7'07 to 1-a striking mutual corroboration of the two methods of calculation and research.

rusting of a given weight of iron is considerably greater than that evolved by its rapid combustion in oxygen, the resulting compound being not only more highly oxidised, but in a state of hydration, or combination with solid water. I may illustrate this to you by a very ordinary experiment. When a plate of copper is immersed in a jar of chlorine gas, for instance, the chlorine gradually combines with the metal, and there is no evident rise of temperature; but when very thin copper leaf is immersed in chlorine gas, the combination takes place instantaneously, with evolution of sufficient heat to render the leaf luminous-with vivid combustion, in fact-as you perceive. Now, the amount of heat given out under these opposite circumstances is identical; the only difference is in its intensity -in the quantity of heat associated with a given quantity of matter at a given moment. In the last case, the action being instantaneous, and the quantity of matter to be heated very small, we have what we call an intense heat-that is, the momentary association of a large quantity of heat with a small quantity of matter; whereas in the other case, the action being gradual, the development of heat is likewise gradual, spread over a long period of time, and asso. ciated with a large quantity of matter; the increased temperature of which is, therefore, at no one moment very perceptible. The terms quantity and intensity of heat are strictly analogous to the terms quantity and velocity of motion. In a pound weight of iron raised to 1000-the melting point of silver, or ten pounds weight raised to 100°-the boiling point of water,-the quantity of heat capable of being imparted—say, to a gallon of cold water substantially the same, though the intensity of the heat is ten times as great in the one case as the other; just as the quantity of motion is the same in a pound weight moving at the rate of 1000 feet, or a ten pound weight moving at the rate of 100 feet per second, although the velocity of motion is ten times as great in the one case as the other. We come, then, to this conclusion-that chemical action, whether rapid or slow, provided only that the same substances react and the same products result, always furnishes the same amount of heat.

With regard to the dynamic value of muscle oxidation, I told you in my last lecture that by the separation of oxygen from carbo-hydrogen a certain amount of heat force was absorbed and rendered latent in the separated bodies, which, by the re-combination of these bodies, was again liberated and rendered sensible. Now, we find that in all re-combinations of separated constituents, the quantity of heat evolved is perfectly definite and invariable. Confining our attention to hydrogen, and speaking in round numbers, we may say that the heat evolved by burning a cubic foot of hydrogen-that is, by combining a cubic foot of hydrogen with half a cubic foot of oxygen-will raise the temperature of 5 cubic feet of water one degree Fahrenheit; or that the heat of burning hydrogen is capable of raising the temperature of 5 times its bulk of water one degree. But we know that the quantity of matter in a body is proportionate to its weight, and accordingly we get a much better idea of the amount of heat developed, by comparing the items gravimetrically rather than volumetrically. Thus we find that the combustion of one part by weight of hydrogen will evolve an amount of heat sufficient to raise the temperature of more than 60,000 parts of water one degree Fahren--is heit, or 34,000 parts of water one degree centigrade. Now, in comparing the amounts of heat given out by the combustion of different substances, it is convenient to have some definite standard of comparison; and the usual continental standard is altogether, perhaps, the most convenient. According to this standard, the amount of heat given out by one kilogramme of water in cooling one degree centigrade, or, of course, the amount of heat absorbed by one kilogramme of water in rising one degree centigrade is called the unit of heat. We find, then, that when one gramme of hydrogen gas is burned into water it gives out 34 units of heat; or it will raise the temperature of 34 kilogrammes-that is, 34,000 times its own weight of water one degree centigrade.

Turning our attention to carbon, we find that one gramme of carbon, in being oxidised or burned into carbonic anhydride, gives out 8 units of heat, or will raise the temperature of 8 kilogrammes that is to say, 8000 times its own weight-of water one degree. Now, the quantity of heat evolved during the oxidation of a given weight of hydrogen, carbon, or any other combustible, is perfectly independent of the rapidity or slowness of the action. Provided only that the same products are formed, the same amount of heat is liberated in their production, whether it takes place rapidly or slowly, violently or gradually. It is only the intensity of the heat, and not its quantity, which varies with the rapidity of the combination. When a stout piece of iron rusts in the air we get oxide of iron produced as the result of the slow burning of the metal, but there is no obvious rise of temperature! On the other hand, when a piece of iron wire is burned in oxygen gas, we have a brilliant combustion, with an intense development of heat. In reality, the products formed in these two cases are not identical, but only allied. Assuming them, however, to be identical, the amount of heat given out in the rapid burning of the metal would be identical with that given out during its slow rusting. The difference is merely that in the one case all the heat is given out in the course of a few seconds, that there is a great quantity of heat produced in a short time; while in the other case this same quantity of heat is developed only during a long series of years. As a matter of fact, the quantity of heat evolved by the slow

Now, let us apply this to hydrogen, one of the fuel constituents burnt in our tissues. If we inflame a mixture of oxygen and hydrogen gases, the combination and evolution of heat being alike instantaneous, we obtain the most intense degree of heat capable of being produced by direct chemical action. On the other hand, if we take the same mixture of oxygen and, hydrogen gases, and cause them to unite slowly by means of spongy platinum, the oxidation is spread over a considerable period of time, and, the heat being developed during a period of many minutes, there is no great manifestation of temperature at any one instant. The quantity of heat is, however, the same in both cases. One gramme of hydrogen in combining with oxygen, whether quickly or slowly, will always evolve 34 units of heat; and one gramme of carbon in combining with oxygen, whether quickly or slowly, will always evolve 8 units of heat. The slow oxidation of so much carbon and hydrogen in the human body will always produce its due amount of heat, or an equivalent in some other form of energy; for while the latent force liberated in the combustion of the carbon and hydrogen of fat is expressed solely in the form of heat, the combustion of an equal quantity of the carbon and hydrogen of voluntary muscle is expressed chiefly in the form of motion. You may remember that I referred in my last lecture to the equivalency subsisting between heat and motion--to the circumstance that so much heat was convertible into so much motion. Accordingly, when we burn hydrogen or carbon, instead of getting the heat force which was exerted in separating them from oxygen remanifested in the form of heat, under certain circumstances we get it manifested in the form of motion.

Let us next consider what are the quantitative relations subsisting between heat and motion. We have taken as

I brought more prominently under your notice in my last lecture. We perceive that muscular exertion does not result from vital force generated within the body, or, indeed, from force of any kind generated within the body, but only from a liberation within the body of pent-up solar force, which at some time or other had been rendered latent in the separated carbo-hydrate of our food on the one hand, and oxygen of our breath on the other. As well observed by Dr. Tyndall,— "It is at his (i.e., the sun's) cost that animal heat is produced, and animal motion accomplished. Not only is the sun chilled, that we may have our fires, but he is likewise chilled that we may have our powers of locomotion.' From the terms in which, upon that occasion, I referred to the fiction of vital force, some physiologists who honoured me by their presence seemed to infer that chemists and physicists were insensible to those important distinctions existing between living and dead matter, which they profess to explain by declaring the former to be possessed, and the latter dispossessed, of vital force. I believe, however, that chemists appreciate in its fullest extent what may be termed the mystery of life, but they look upon the physiologists' explanation as a mere periphrasis, -as only another mode of saying that dead matter differs from living matter because it is dead, while living matter differs from dead matter because it is alive. Chemists and physicists are well assured that, be life what it may, it is not a generator, but only a transformer, of external force. In the vegetable kingdom solar force is absorbed, in the animal kingdom it is liberated by the eremacausis of our fat and muscle.

Besanez's experiments upon the oxidation effected by ozone in alkaline liquids, whether or not a series of bodies intermediate between the initial substance and final carbonic acid are really formed, we are quite incapable of detecting them, and, consequently, of tracing their metamorphoses. The constituent carbon atoms of the original substance seem, at any rate, to become at once completely isolated, and oxidised. Whether, therefore, the more complex molecules formed by natural tissue-oxidation are to be regarded as direct, but intermediate, products of the principal oxidation, or as bye products resulting from subsidiary processes, is at present an open question, though the balance of evidence with regard to certain products, at any rate, seems to be in favour of the latter view. In any case, however, the formation and even excretion of some or other of these bodies, in greater or less proportion, according to the nature of the organism,-uric acid largely in birds and land reptiles, hippuric acid largely in herbivora, and both acids sparingly in mankind-are obviously normal or healthy actions. By the excretion of such imperfectly burned substances, indeed, a certain amount of force does not become utilised within the animal, but this prodigality of force in organic nature is far inferior to that which we observe in the inorganic world.

(To be continued.)

BRITISH ASSOCIATION. Birmingham Meeting, President, Professor PHILLIPS, M.A., &c., &c.

union of fresh discoveries and new inventions with the

President's Address, delivered September 6. Now, the full realisation of the force derivable from a given weight of muscle depends upon its complete oxida- ASSEMBLED for the third time in this busy centre of industion into water and carbonic acid or urea. Should it be trious England, amid the roar of engines and the clang of only converted into sugar, or kreatine, or uric acid, these hammers, where the strongest powers of nature are trained are imperfectly burned substances, which still retain a to work in the fairy chains of art, how softly falls upon certain amount of potential energy liberable from them by the ear the accent of Science, the friend of that art, and further oxidation. They still contain associated with them the guide of that industry! Here, where Priestley anasome portion of the latent force put into the original tissue-lysed the air, and Watt obtained the mastery over steam, constituents at the period of their formation, and accord- it well becomes the students of nature to gather round the standard which they carried so far into the fields of knowingly, by their further oxidation, we are capable of getting an additional amount of work out of them. ledge. And when, on other occasions, we meet in quiet In order, therefore, to obtain the full equivalent of heat colleges and academic halls, how gladly welcome is the force or motive force to which we are entitled by the waste of our tissues, it is important that this waste should be solid and venerable truths which are there treasured and thorough, that both the hydrogen and carbon should be taught. Long may such union last; the fair alliance of converted into the most completely oxidised compounds cultivated thought and practical skill; for by it labour is they are susceptible of forming, the whole of the hydro- dignified and science fertilised, and the condition of human gen into water, and the whole of the carbon into its society exalted! most stable mono-carbon compound, namely, carbonic acid, or the ammoniated form of this acid, namely, urea. In some cases of imperfect oxidation, however, we get less oxidised, and more complex, dicarbon molecules produced, such, for example, as oxalic acid, which occurs either in its normal saline state, or colligated with urea in the form of allantoine, oxaluric acid, &c. In cases of yet more imperfect oxidation, we meet with still less oxidised tricarbon molecules, such, for example, as the mesoxalic compound, which forms uric acid by its colligation with urea. We may even have tetracarbon molecules such as succinic acid, pentacarbon molecules such as amido-valeric acid or phocine, hexacarbon compounds such as amido-caproic acid or leucine, and heptacarbon compounds such as the benzoic residue of hippuric acid, and the salicic residue of tyrosine.

In certain processes of artificial oxidation to which I referred in a former lecture, we obtain, as you may remember, from any particular substance a series of less and less complex bodies terminating in carbonic acid; or, to use again the words of Gerhardt, we gradually descend the scale of complexity, converting the original substance into more and more simple products by successively burning off a portion of its carbon and hydrogen. In other cases, however, as in Gorup

Through this happy union of science and art, the young life of the British Association,-one-third of a century,inventions in a degree never surpassed. How else could has been illustrated by discoveries and enriched by useful we have gained that knowledge of the laws of nature which has added to the working strength of a thousand millions of men the mightier power of steam*, extracted from the buried ruins of primeval forests their treasured elements of heat and light and colour, and brought under the control of the human finger, and converted into a messenger of man's gentlest thoughts, the dangerous mystery of the lightning ?†

How many questions have we asked-not always in vain regarding the constitution of the earth, its history as a planet, its place in creation ;-now probing with sharpened

The quantity of coal dug in Great Britain in the year 1864 appears by the returns of Mr. R. Hunt to have been 92,787,873 tons. This would yield, if employed in steam engines of good construction, an amount of available force about equal to that of the whole human race. But in the combustion of coal not less than ten times this amount of force is actually set free-nine-tenths being at present unavailable, according to the statement of Sir William Armstrong, in

his address to the meeting at Newcastle in 1863.

The definite magnetic effect of an electrical current was the discovery of Oersted in 1819; Cooke and Wheatstone's patent for an electric telegraph is dated in 1837; the first message across the Atlantic was delivered in 1858. Tantæ molis erat.