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

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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$oxygen sufficient to form arsenious acid, it does not possess the slightest poisonous properties. Btinsen, to whom we owe these remarkable observations, found that frogs, who are poisoned even with the fraction of a grain of arsenious acid, were unaffected by a grain of kakodylic acid. In the experiments on dogs, six grains were introduced into the stomach ; in another experiment seven grains were injected into the jugular vein ; and in a third, four grains were introduced into the lungs without producing any in- jurious effects. This negation of the toxic influence of one of our most deadly poisons admits only of explanation on the hypothesis of the different grouping of atoms, or, in other words, the differences of chemical constitution. It would indeed lend no small support to the hypothesis of Dumas, that variations in physical arrangement have more to do with developing some of the most prominent properties of bodies, than differ- ences in the chemical nature of the consti- tuent molecules. Every one who has traced the develop- ment of physiological chemistry must have had one great fact impressed upon him— that the more our knowledge has extended, the less are we obliged to appeal to the so- called vital force to explain the changes going on in the organism. But a few years ago this was almost the only explanation which could be afforded to most of the chemical phenomena of life; but as our experience has extended, we find more and more that recognised chemical and physical forces constitute the keys employed to unlock their penetralia. That we are still obliged to refer much to this vital force is true, but it is equally true that this becomes each year less and less. It may, and to the uninitiated must, appear presumptuous for the chemist to venture to explain the gene- ration of elements in the body by a reference to chemieal formula? ; and it has been indeed triumphantly remarked, that, although it is possible to make out on paper how urea, or uric acid, or bile, may be formed from the waste of tissues, or re-arrangement of the elements of food ; still the chemist cannot, with all the appliances of his art, and all his ingenuity, produce either urine or bile from a beefsteak. This indeed is true to a certain extent; and, as far as it goes, the objection may at present be regarded as im- portant; still, I suspect, those who would urge these remarks are scarcely aware bow much the chemist can really effect. His art has actually enabled him in very many in- stances to produce in his glass vessels the very same results which are presented to us in the organised world as the results of the chemistry of life. A volume might now be filled with an account of such chemical miracles; and the metamorphoses of che- mistry might, to those who first heard of them, appear as fabulous as those recorded in the verses of Ovid. A few examples of what can be thus effected will merit a pass- ing notice. You all know that a curious crystalline substance, urea, is an essential element of the secretion of the kidneys j that during the waste of our tissues they are metamor- phosed into this, among other bodies. I now shew you a specimen of this urea, and, at the same time, tell you that this was never formed by the vital forces, but by the chemistry of art. In some forms of mal- assimilation, a person eating a hearty meal of flesh has a great part of it converted into urea in the body, and the results of his re- pletion got rid of by the kidneys. The very specimen I now shew you was actually made artificially from animal matter. A mass of any animal tissue, or blood, being mixed with a little carbonate of potass, and heated until the whole is decomposed; the carbon, hydrogen, nitrogen, and oxygen, undergoes a series of changes. A portion of the first and third unites to generate cyanogen, which, with the potassium, forms a cyanide of potassium. This salt, absorbing oxygen, become scyanite of potassa, and, when mixed with a solution of sulphate of ammonia, forms a cyanite of ammonia, which at a boiling heat becomes urea. Thus the chemist, by decomposing with alkalies a piece of flesh in his crucible, obtains one of the very products which would have been generated, if, instead of submitting it to this influence, it had been simply swallowed. No one, in strolling through the country in the autumn, can have avoided noticing an elegant plant ornamenting the banks of every stream with its abundance of pale yellow flowers, and filling the air with its sweet odour, not unlike that of bitter al- monds. This is the Spiraea Ulmaria, or queen of the meadows. The odour to which I have alluded depends upon an essential oil obtained by distillation with water, and possessing very remarkable properties, and having a composition of Cl4 H0 04 = C14 Hs 04 + H = Sa, H. It will surely be deemed no small thing to make this oil artificially; yet nothing is easier. Not far from the Spiraea, one or other of the different willows or osiers are sure to be found. Now the barks of these trees owe their bitterness and anti-periodic virtue to this white body called salicine, having the following composition:— C2a H18 014. Now, on comparing these formulae, it will be seen at once that but two atoms of oxygen are required to be added to salicine$