Lectures on the influence of researches in organic chemistry on therapeutics : especially in relation to the depuration of the blood / delivered at the Royal College of Physicians, by Golding Bird.

  • Bird, Golding, 1815-1854.
Date:
1848
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Licence: Public Domain Mark

Credit: Lectures on the influence of researches in organic chemistry on therapeutics : especially in relation to the depuration of the blood / delivered at the Royal College of Physicians, by Golding Bird. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    needles I now shew you, and the oxide of lipyle, at the moment of its separation, uniting with water to form the hydrated oxide—this sweet compound well known as glycerine. Now we cannot re-form mutton fat by mixing glycerine with stearic acid, simply because we cannot present these bodies to each other in an active state : they will no more combine than will the acetic acid and ether in the last example. But if we take a hydrated latty acid—the butyric— a specimen of which I now shew you, (pre- pared by the fermentation of sugar,) mix it with glycerine, and, adding sulphuric acid, digest the whole with a gentle heat, the water will leave the butyric acid and gly- cerine, and the nascent elements of the acid and oxide of lipyle will combine to form the butyrate of lipyle, or, in other words, butter. In this way, butter can be artificially made from the fatty base of mutton fat and the results of the fermentation of sugar. To borrow a remarkable, and, as we shall by and by see, an important illustration from the animal economy. It is well known that the hippuric acid so largely excreted by graminivorous animals, and which, in the state of hippurate of potass, exists to the amount of 16'51 grains in 1000 of the urine of the cow, and of 4*74 in that of the horse, may have its composition represented by C H N O Benzoic acid . 14 5 0 3 + Glycocoll ..4413 = Hippuric acid .18 9 1 6 And if we boil hippuric acid with hydro- chloric acid, it is easily separated into benzoic acid and hydrochlorate of glycocoll, from which the glycocoll or sugar of gelatine can be easily separated. And I now shew you specimens of these two bodies separated from some of the hippuric acid now before you, and which I prepared from the urine of one of my horses after a night's rest in the stable. Now by no ingenuity can I succeed in recoinbining the benzoic acid with the glycocoll to reconstruct the hippuric acid, and for the very same reason that I failed in causing acetic acid and ether to unite. If now the benzoic acid encountered the 4 atoms of carbon, 4 of hydrogen, 1 of nitrogen, and 3 of oxygen, at the moment of their evolution in a free state from de- composing animal matter, they would un- doubtedly unite to form hippuric acid. Now, as we do not at present know how to obtain these elements in a nascent state, we cannot submit this to the rigid test of ex- periment in the laboratory. We, however, can without difficulty obtain this result in another way. It is universally admitted that the material elements of our tissues are always in a state of change, that at each moment of our existence effete and exhausted tissues are in a state of metamorphosis, the ultimute element separating under the dis- organizing influence of inspired oxygen to form the elements of excretions. Thus, we have constantly in the wonderful laboratory of our frames ultimate atoms in a state of active chemical tendency, or, in other words, in a nascent state. If, then, when such atoms of carbon, hydrogen, nitrogen, and oxygen, (in a state of high chemical tension, at the instant they are set free from their previous union, when forming part of the structure of any organ,) come in contact with benzoic acid, they at once combine with it in the same proportion in which they exist in sugar of gelatine, and hippuric acid results. If any person swallows thirty or forty grains of benzoic acid, it will be ab- sorbed with his blood, and in the capillaries will come in contact with the elements in question; hippuric acid will be generated, and, in accordance with the law of all soluble matters in the blood not required for the purpose of nutrition, filtering off by the kidneys, it will be found readily in the urine. The specimen I now shew you was thus prepared from the urine of a patient to whom 1 had administered benzoic acid. This contains all the benzoic acid I gave him, plus carbon, hydrogen, nitrogen, and oxygen, in the proportion to form sugar of gelatine. It does not necessarily follow that these elements be always separated in the proportion to form glycocoll: if we throw into the system a body which differs in its composition from it, in a ratio quite distinct from that of benzoic acid, still the nascent atoms will be seized to form hippuric acid. The beautiful substance I now shew you is cinnamic acid—a body readily formed by the oxidation of the oils of cassia and cinna- mon, and existing abundantly in the balsam of Peru. This consists, in its crystallized state, of C18 H„ 04, and may be administered with impunity as a medicine. We see that this body differs fiom hippuric acid only in the absence of nitrogen and oxygen ; for C H N O Hippuric acid (dry). 18 8 1 5 Cinnamic acid ..188 4 1 + 1 And, when taken as a medicine, this body appropriates to itself more than 8 per cent, of the nitrogen evolved from the exhausted tissues to form hippuric acid, which then appears in the urine. The administration of the glycocoll, to which I have just drawn your attention, affords us another instance of this appro- priation of the nascent atoms of exhausted