caseine, and examine the solution with the spectroscope. One band and a doubtful second in the positions of the other luteine bands, will be perceived.

The solution will deposit crystals of cholesterine. Examine also the ether and chloroform solutions.

Compare with the above a chloroform extract of dried fæces of adults. It will give no band.

Lymph.-1. Examine under the microscope; white corpuscles and fat globules will be noticed.

2. Allow fresh drawn lymph from a blister, or a fistula of a lymph vessel to stand; it will coagulate. Remove the coagulated threads by beating with a bundle of twigs, and wash them with water. They will be found to consist of fibrine (see Fibrine).

3. Strain the liquid and heat it to boiling. A precipitate of albumen in flakes will be produced.

4. Filter; to the hot filtrate add a slight excess of dilute sulphuric acid; allow to cool, and shake repeatedly with small portions of ether. Evaporate the ether to dryness, and digest with water. The part

insoluble in water will consist of fats. The soluble portion will contain lactic acid (q. v.).

5. Dry a portion of fresh lymph at 100° C., powder the residue, and burn to a white ash. Examine the ash it will contain sulphate, phosphate, carbonate, &c., of the alkalies, and a small quantity of earthy salts. Notice prevalence of soda over potash salt.

Melanine. The black pigment of the eye or of melanotic cancers must be isolated as much as possible, and purified by solution in ammonia and precipitation by hydrochloric acid. It will possess a composition similar to uromelanine (q. v.), but different properties. A portion will be found to be quite insoluble in any ordinary reagent.

Milk.-1. Milk has a specific gravity 1.018 to 1.045.

2. Test the reaction with litmus paper; the reaction is usually alkaline.

3. Examine some milk under the microscope; it will appear as a clear liquid, in which float the milk globules. These vary in diameter from about 0.0012 to 0.0030 inch.

4. Add a little acetic acid to milk; the globules will become distorted.

5. Shake up some milk with ether; the globules, though they consist of fat, are not dissolved. This is due to the fact that each globule has an envelope which is insoluble in ether.

6. Shake up some milk with caustic potash, which

dissolves the envelope. On now treating with ether the globules will be dissolved.

7. The colostrum (milk secreted during the first two or three days after parturition) is characterised by the presence of granular bodies. Examine under the microscope: the granular bodies will be seen to be composed of irregular aggregations of small fat globules, and united by an albuminous amorphous granular substance. Treat with iodine water; the albumen will be dyed yellow. Potash and acetic acid break up these granular bodies.

8. Evaporate 20 cc. of milk to dryness in a small weighed porcelain or platinum crucible on the waterbath. Dry in an air-bath for several hours at 110° C. and weigh; the increase in the weight of the crucible gives the solid residue in the milk.

9. Ignite the dried residue over a Bunsen or Argand burner; allow to cool and weigh. The difference between this weight and the original weight of the crucible gives the ash of the milk.

Milk contains about 10% solid residue, and 0.1 to 0.5% of ash.

10. Evaporate 50 cc. of milk on a water-bath almost to dryness in a weighed porcelain dish; add acetic acid. Exhaust the residue successively with ether, alcohol, and water. Dry the exhausted residue and weigh; the increase in the weight of the dish gives the caseine in the milk.

11. Evaporate the ethereal extract to dryness in a weighed crucible and weigh; the increase of weight will give the quantity of fat.

12. Add to 100 cc. of milk solution of calcium chloride; the caseine is precipitated; filter; add potash solution to precipitate excess of calcium, and estimate the sugar present in the filtrate with standard solution of potassio-tartrate of copper.

Milk contains 2 to 4% caseine.

Mucine.-1. Dilute mucus with four vols. of water and filter. Digest the insoluble matter (mucine) with a weak solution of potash, filter, neutralise with acetic acid, wash the precipitate with water, alcohol, and ether, and use it for the following reactions.

2. Dry a portion and burn on platinum foil. A white alkaline ash containing calcium phosphate will remain.

3. Fuse with caustic potash, dissolve in water, and add a drop of lead acetate. No black precipitate, showing the absence of sulphur.

4. Mix with cold water and boil. It will gradually dissolve. Add alcohol; the mucine will be precipitated in flakes.

5. Dissolve mucine in a dilute acid or alkali, and add potassium ferrocyanide. No precipitate.

6. Dissolve in glacial acetic acid and boil. Add potassium ferrocyanide; white precipitate.

7. Heat with concentrated nitric acid: the mucine will turn yellow and dissolve.

8. Dissolve in very weak caustic potash, and add basic lead acetate or tannic acid; white precipitate.

9. Dissolve in dilute hydrochloric acid, and add mercuric chloride; only a slight turbidity will ensue.

Muscles.-Striated voluntary and involuntary muscles. -1. Examine under microscope. They will be found to consist of fibres bound together in bundles, and marked with transverse striæ.

2. Free the muscles of a recently-killed animal from blood by injecting through the vessels a one per cent. solution of sodium chloride. They must then be frozen, minced, mixed with four vols. of snow containing a little sodium chloride. The mass will liquefy, and must be quickly filtered at 0°C. The nearly clear filtrate on regaining the ordinary temperature will coagulate. Stir with a rod, and separate the coagulum from the serum.

3. Wash the coagulum with water, alcohol, and ether. It will be found to consist of myosine (q. v.). 4. Heat the serum to boiling: albumen will precipitate in flakes.

5. Extract the cake which remains after the extraction of myosine and albumen by process 2 with pure water, and observe that the red colouring matter myochrome, identical with hemato-crystalline, dissolves. Study its properties as prescribed for hematocrystalline.

6. Expose a piece of fresh muscle to oxygen under a receiver, and observe that oxygen is absorbed and carbonic acid evolved.

7. After extraction of the myochrome (5), treat the