PRESENTATIONS AND POSITIONS OF THE FŒETUS. 215

of the pelvis. (This is the conversion of the second vertex position.)

Third. The forehead points to the right sacro-iliac synchondrosis, the chin to the left foramen ovale, and the long diameter of the face lies in the right oblique diameter of the pelvis. (This is the conversion of the third vertex position.)

Fourth. The forehead points to the left sacro-iliac synchondrosis, the chin to the right foramen ovale, and the long diameter of the face lies in the left oblique diameter of the pelvis. (This is the conversion of the fourth vertex position.)

SHOULDER PRESENTATIONS.-These include two divisions, those in which the back of the child looks to the abdomen of the mother, and those in which the back of the child is turned towards the spine of the mother. Each of these is subdivided into two classes, according as the head of the child is placed in the right or left iliac fossa. In dorso-anterior positions, if the head lie in the left iliac fossa, the right shoulder of the child presents; if in the right iliac fossa, the left. In dorso-posterior positions, if the head lie in the left iliac fossa, the left shoulder presents; if in the right, the right.

BRIEF RULES FOR CLINICAL EXAMINATION OF THE URINE.

The following rules for the examination of a specimen of urine will be found of value to the practitioner as a guide to the proper method of investigating the abnormal conditions of that fluid.1

1. Color. Whether pale from being dilute, dark from being concentrated, dark or greenish from presence of bile, smoky from blood.

2. Smell.-Fragrant from the existence of cystin, or sugar, etc., or fetid from alkalinity.

3. Quantity passed in twenty-four hours, to be measured; observe whether there is excess or diminution.

4. Specific Gravity.-Take the specific gravity, if pos sible, of the mixed urine. Normal sp. gr. 1020. If high, suspect sugar; if low, suspect albumen.

5. Reaction. If acid, is it normally so or not? If excessively acid, examine for crystals of uric acid. If alkaline, ascertain whether the alkali is fixed or volatile.

6. Heat.-Heat a portion in a test-tube. If a precipitate appear, it may be albumen or phosphates. Add a drop or two of nitric or hydrochloric acid. If precipitate dissolve, phosphates; if not, albumen. If a deposit disappear on heating, we have urates. If it do not disappear, add a drop of nitric acid. If now dissolved, we have phosphates; if not, cystin.

7. Bile.-Test for bile pigment and bile acids, if neces

sary.

1 Arranged ard condensed from J. Hughes Bennett's Text-Book of Physiology, pp. 478-485; Philadelphia, 1873.

8. Sugar. Test for sugar, if necessary.

9. Chlorides. Add a drop of nitric acid, and then nitrate of silver, until a precipitate ceases to form. Thus estimate the average of chlorides.

Microscope.-Examine for blood, pus, cystin, oxalate of lime, leucin, tyrosin, tube-casts, etc.

Mode of Detection of Abnormal Constituents of the Urine.

The abnormal constituents of the urine are the following albumen, bile acids and pigment, acetic, lactic, and butyric acids, fat, sugar, kiestein, leucin, tyrosin, allantoin, sulphuretted hydrogen.

ALBUMEN.-1. Heat.-If the urine be alkaline to testpaper, or neutral, add a few drops of acetic or nitric acid; 1; if very acid, neutralize with a little dilute ammonia. Boil a small quantity in a test-tube. If albumen be present, urine becomes turbid if the heat exceeds 154° Fahr.; if albumen abundant, distinct coagulation occurs. If the urine before examination is too acid or too alkaline, coagulation will be prevented by the union of the albumen with the acid or the alkali respectively. In some varieties of urine, boiling produces a precipitate of earthy phosphates, which dissolve on the addition of a little dilute nitric acid.

2. Nitric Acid.-This acid produces white turbidity when albumen is present in small quantity; distinct coagulation, if in large quantity. If soluble nitrate of albumen is formed, no coagulation occurs; if nitrate of urea be precipitated, the microscope will detect it. If the patient has been taking copaiva, cubebs, or other oleaginous or oleo-resinous medicines, the urine may be turbid, but the turbidity does not sink, but remains for hours. suspended in the fluid.

It is better to employ both heat and nitric acid than either alone.

3. Ferrocyanide of Potassium.-Add to a well-filtered urine, acidulated with acetic acid, a weak solution of the ferrocyanide (gr. v to f3j); a white precipitate occurs, but if there is much mucus in the urine, the test is not serviceable.

SUGAR. Sugar in excess in the urine is grape sugar, often termed diabetic sugar. The urine in diabetes is usually light-colored, froths readily when poured from vessel to vessel, and has a high specific gravity. To obtain the sugar, evaporate the urine to syrupy consistence, and allow the sugar to crystallize out. Separate from it the urea and extractive matters by absolute alcohol, and add to the residue spirits of wine to dissolve the sugar, which is allowed to separate, and the crystalline masses are then purified from alcohol by repeated re crystallizations from water.

The tests for sugar in the urine are the following:—

1. Moore's Test with Caustic Potash.-Add to the urine an equal bulk of solution of caustic potash, and boil. If sugar be present, a dark sherry color will be obtained; if in large quantity, a dark purple, sometimes almost black. The caustic potash, unless freshly prepared, may be contaminated with lead of glass bottle, producing a sulphide of lead when added to urine.

2. Trommer's Test with Sulphate of Copper and Caustic Potash. This test depends on the fact that diabetic sugar has the property of reducing cupric to cuprous oxide; but an excess of urates or the protein compounds occasionally present in urine unfortunately have the same property. We may be sure that diabetic sugar is present if cupric oxide be thus reduced in the cold. The process is to add to the urine a few drops of solution of sulphate

of copper; to this add a little caustic potash. A greenishblue precipitate of hydrated cupric oxide results, which is dissolved in an excess of the caustic potash, forming a blue liquid. Heat this by applying the flame of a lamp. to the upper stratum; if sugar be present, a yellow, or orange, or red precipitate of cuprous oxide will be formed, in marked contrast to the blue liquid at the bot tom of the test-tube.

3. Fehling's Test with Potassio-cupric Tartrate.—This compound is made by dissolving 34.65 grammes of pure crystallized sulphate of copper in about 160 grammes of water. This solution is gradually poured into a solution of 173 grammes of pure crystallized double tartrate of potash and soda, treated with from 600 to 700 grammes of caustic potash of 1.12 sp. gr. The clear mixture is then diluted up to a litre. When a few drops of this potassio-cupric tartrate solution are added to the urine, and the upper stratum boiled, the cupric oxide in the alkaline tartrate is reduced to the cuprous oxide, if sugar be present, as in Trommer's test. Ten cubic centimetres. of the alkaline solution are reduced by exactly 0.05 gramme of diabetic sugar. Fehling's solution is, however, liable to decomposition, even if kept for only a week, and sometimes gives uncertain results.

4. Böttcher's Test with Nitrate of Bismuth.-Add to the urine an equal volume of a solution of one part of crys tallized carbonate of soda to three parts of water, and afterwards a little trisnitrate of bismuth, and boil. If sugar be present, the white powder will become dark, the oxide of bismuth being reduced by the sugar. Any albumen in the urine should first be got rid of by boiling and filtration, otherwise the sulphur of the albumen may form the black sulphide of bismuth.

5. Dichloride of Tin Test.-Moisten a few strips of me