rine urine. In the contrary case, the plane of polarization is said to be diverted towards the left.

The angle in which the hand has to be turned is proportionate to the concentration of the fluid and the length of the column through which the polarized light has to pass, viz., to the length of the tube in the apparatus. In Mitscherlich's apparatus, the length of the tube is 200 millimètres (7 English inches).

Supposing a fluid of a certain concentration to be put into the tube, the hand standing at zero, and that in order to see one half of the spectrum violet, the other red, a rotation of the hand of 40° be required, then the same fluid in a tube of half the length would turn the hand only to 20°.

On the other hand, if 15 grammes of sugar be dissolved in any certain quantity of water, and the solution be poured into the tube so as to fill it; and if then the hand be turned until the colours of the zero point appear for which we will assume a rotation of 15° to be requisite then a solution of 30 grammes of sugar in the same quantity of water as the 15 grammes were dissolved in, when filled into the tube, will require exactly double the rotation, namely 30°, for the testcolours to appear.

It has been found by accurate experiments that 15 grammes of pure and dry grape-sugar, when dissolved in so much water that the solution amounts to exactly 50 cubic centimètres, will make a fluid, a column of which, 200 millimètres in length, will turn the plane of polarization 40° towards the right.

Upon the basis of this experiment it is easy to determine the amount of sugar in any fluid. Supposing the above tube, full of bright, faintly yellow diabetic urine, requires a movement of the hand from 0 to 30, then

which, in other words, means that, with a rotation of 30°, there are 11.25 grammes of sugar contained in 50 cubic centimètres of this diabetic urine. Another equation shows the amount of sugar contained in the urine passed during a certain length of time.

It is not possible to approximatively determine the amount

of sugar from the specific gravity of urine, as has been shown by Dr. Bence Jones.'

Pathological indications of Sugar in Urine.

It has been stated that the urine of healthy persons occasionally contains sugar; it has also been stated that the urine of pregnant and suckling women is always impregnated with sugar, in the latter in a direct proportion to the amount of milk secreted by the breasts. These assertions theoretically, that is, viewing them from the aggregate of known facts, seem to be deserving of but little confidence. It is certainly incumbent upon the authors who made those assertions to prove that the substance which in their experiments gave the reaction of sugar, was really grape-sugar and nothing else.

In the course of some cases of acute disease, the temporary appearance of small quantities of sugar has occasionally been observed. In these cases, also, doubt has not been perfectly excluded, so that a pathological explanation cannot be attempted.

When the urine contains large quantities of sugar for a length of time, there is reason to believe that diabetes mellitus is present. The diagnosis is ensured by collateral symptoms of this disease, which as yet has eluded the most vigilant researches of physiologists. Some of these symptoms are, a large amount of urine of high specific gravity, great thirst, emaciation, dry skin, the appearance of boils, gangrene of parts most remote from the circulating centres, and tubercular consumption of the lungs.?

When grape-sugar in concentrated solution is injected into the veins of animals, a part reappears in the urine after a short time. When, however, the solution is dilute, although the same quantity of sugar be injected in such solution as in the concentrated one, no sugar appears in the urine afterwards.

If the liver be freed from blood by washing the vessels with water, an extract made of a part of such liver will yield no sugar. If, then, the liver be allowed to remain exposed to the air for a variable length of time, sugar may be de

1 Med. Times and Gaz.,' February 4, 1854.

For a review of the present state of the doctrine of diabetes mellitus, see Dr. Garrod's Gulstonian Lectures on Diabetes and Saccharine Conditions of the Urine, British Med. Journ.,' April, May, and June, 1857.

C. F. Kersting, Saccharum sanguine receptum in urinam transire probatur experimentis,' Missenæ, 1845, viii, p. 12.

tected in the liver. It must have formed from substances in the liver, under the influence of oxygen, as in an atmosphere of hydrogen no sugar is formed. The substance found in the liver by M. Cl. Bernard, and capable of transformation into sugar, is a body nearly allied to dextrine, as has been confirmed by Pelouze.

The observation of M. Cl. Bernard, that the liver of carnivorous animals always contains sugar, does not prove that sugar is formed from albuminous substances. The meat and flesh eaten by carnivora contains inosite, which has the same elementary composition as grape-sugar, and tastes sweet, and is only different by its form of crystallization, greater amount of water of crystallization (4HO), and a few tests and reactions. This body might possibly be transformed into grape-sugar. It has long since been known that the milk of carnivora contains sugar proper to milk. This possibly may be derived from the inosite of flesh.

There is no foundation for the opinion of M. Mialhe, that grape-sugar, physiologically, is oxydized by the mediation of the bicarbonates of the alkalies, and that in diabetes it may be assimilated by means of these salts.

Some authors make a difference between diabetic sugar from animals and grape-sugar from plants, and assign to them different bearings in the economy. This idea, which seems to have emanated from some experiments with substances of a doubtful nature, is not supported by such evidence as can be considered sufficient by the present demands of chemistry.

The quantity of sugar in the urine of diabetic patients is diminished, or sugar is altogether absent for a short time, under the influence of the following circumstances:

Total abstinence from food.-Hence the urine in the morning is sometimes free from sugar.

Perfect rest in bed.-Sugar becomes less in quantity and disappears for a day or two. It reappears as before on the patient taking exercise.

Meat diet has the most important influence upon the quantity of sugar, which becomes very much smaller. It is the most important palliative in diabetes.

The remarkable experiment by M. Bernard, in which a wound inflicted upon the bottom of the third ventricle of the brain of dogs, causes sugar to appear in the blood and urine of the animal in a very short time, remains unexplained.

ACETONE is produced by the dry distillation of acetates, particularly the salts of lime, baryta, magnesia or lead, or by exposing acetic acid to red heat. It is further one of the products of dry distillation of sugar, tartaric acid, and other bodies, and as such occurs in the common pyroligneous or pyroacetic spirits.

Physical and Chemical Properties.

Acetone is a colourless thin liquid of 0.814 sp. gr. at 0° C., and boils at 56° C. It is soluble in water, alcohol and ether, and may be mixed with them in any proportion. Like alcohol, it dissolves many substances which are insoluble in water, such as resins or pigments. In contact with the hydrate of an alkali and oxygen it becomes brown, and transforms into a resinous substance. On passing the vapours of acetone over heated potassa lime, hydrogen is evolved, acetate and formiate of potassa remaining.

Acetone in the Urine of diabetic patients.1

The urine of diabetic patients has a peculiar odour, which has been noticed by most authors on the subject of diabetes. Thus Hodges 2 describes the odour of diabetic urine as that of sour milk, Corneliani as that of violets. Th. Hodgkin 3 remarks that glasses which have during a longer time served for the purpose of determining the specific gravity of diabetic urine, evolve a distinct odour of musk. The same odoriferous substance occurs in other excretions of these patients.

'Petters, Untersuchungen über die Honigharnruhr, Vierteljahrschrift für die Pract. Heilkunde,' Prag, 1857, vol. iii, p. 81.

2

London, Med. Gaz.,' 1843.

3 Assoc. Med. Journ.,' 1854, No. 93.

It was noticed by Hodgkin in the fæces, containing little colouring matter of bile. Rother1 found that the body of a diabetic patient, who had been treated with creosote, smelled of vinegar. The breath of diabetic patients is compared, by Brand, to the smell of apples, and to the breath of persons to whom pure chloroform has been administered. Other authors observed the odour of new hay; and Berndt found the breath of a patient treated with creosote to give first the odour of horses' urine (from the creosote or carbolic acid), and afterwards that of young beer. Petters himself found the odour very peculiar, a mixture of sweet and acid, and compares it, in a concentrated form, to the odour of a mixture of chloroform and acetic ether or aldehyde ; when dilute, however, as it always is in the exhalations, he found it more like that of very dilute ammonia,-under all circumstances, however, so peculiar, as frequently to lead the physician to the diagnosis of diabetes. Petters also found that the urine of persons suffering from measles or scarlatina evolved the same odour.

It appears that Dr. Lerch, Director of the Institute for Animal Chemistry at Prague, suggested to Dr. Petters the probability of the odoriferous body in the excretions of diabetic patients being acetone. The latter author succeeded in establishing the presence of acetone in the urine, blood, and most parts of the body of a patient, of whose case the following is a brief outline.

A Jewess, thirty years old, shopwoman, was admitted into the Prague Hospital. She had undergone much privation, and consequent depression of mind, during the last eighteen years. Latterly she had been treated as an out-patient for constipation. Five weeks before admission she was suddenly attacked by violent pain in her stomach, and repeated vomiting. The bowels had been confined during six days. She was relieved by a purgative, and returned a week afterwards, complaining of continued great thirst. She also admitted to pass urine more frequently and in larger quantities. Dr. Grün established the diagnosis of diabetes by the discovery of sugar in her urine. The symptoms now continued to increase in intensity, the pain in the stomach and vomiting returned, and she at last consented to be received into the hospital.

On her arrival she vomited. Her tongue was found a little moist; the saliva had an acid reaction. The breath