CONNECTIVE TISSUE CORPUSCLES.

Make a gold preparation of tadpole's tail.

This will show the connective tissue corpuscles very well with their branched processes. Pigment cells are also numerous. Several of these preparations should be made, as they show a great many different

structures.

Make a preparation of newt's mesentery in 5 per cent. chromate of ammonia (page 19), and double stain with picro-carmine and logwood (page 52). In this preparation very large branched corpuscles will be seen having the hyaline ground plate stained with logwood; these make most beautiful objects for examination with high powers.

The corneal corpuscles will be mentioned in another place.

TENDON.

To show the tendon cells which lie in the interfascicular lymph spaces, take a young mouse just killed and remove the skin of the tail, then with the forefinger nail separate two of the caudal vertebræ and forcibly remove the distal portion. Several white

threads will be left, these are the tendons. Take a small bit of one of the finest and place it in slightly acidulated water for a short time, then remove to half per cent. gold solution, let it remain about.

H

twenty minutes.

Then place it in distilled water, which must be changed once or twice, until it becomes a brown colour. Take a small bit and place it in a drop of glycerine on a slide, and separate it into as many fibrils as possible. Cover and examine.

Take the tail of a young rat and prepare it in gold chloride (page 19). Make transverse sections and double or treble stain them. The tendon cells will be seen, darkly stained with the gold, lying between the bundles of fibrous tissue forming the tendons.

Tendon should also be examined in the fresh state, by taking a small portion from the mouse's tail and mounting in salt solution, then irrigating it with very dilute acetic acid, and watching the change that takes place, as the fibrous tissue swells up and becomes indistinct, the cells becoming granular.

The acetic acid should be only just sour to the taste. After a time the whole of the fibrous tissue will have disappeared, leaving a very few elastic fibres which are untouched by the acid.

Take also some of the fresh tendon and place it in logwood stain, to which a few drops of glycerine have been added; let it remain until deeply stained. Tease out small portions in glycerine on a slide; the tendon cells will be well shown by this process.

ELASTIC TISSUE.

Make a preparation of mesentery of frog and mount in glycerine; a very fine network of elastic fibre will be found throughout the whole structure.

Take a small slice of the ligamentum nucha of the ox, which can be readily procured from the butcher's. Place it in dilute acetic acid for some little time, until it swells up, then tease a small portion in a drop of glycerine on a slide. Cover and examine.

WHITE FIBROUS TISSUE.

Is well shown in many of the preparations of serous membranes. A special preparation should, however, be made, by hardening omentum in 1 or 2 per cent. bichromate of potash and staining with logwood; it will show the large amount of fibrous tissue present in a serous membrane, forming the greater part of the framework.

White fibrous tissue is also well seen in sections of skin; also in submucous tissues.

ADIPOSE TISSUE.

Well seen in some of the preparations of serous membrane, when the fat cells lie thickly along the sides of the blood vessels.

and in many other parts.
a special preparation of it.

Also seen in cutis vera,

It is not necessary to make

A serous membrane placed for a short time in dilute osmic acid, and mounted in glycerine, will show the fat cells differentiated from the surrounding tissue, as they have all become blackened by the action of the osmic acid.

CARTILAGE.

HYALINE CARTILAGE.

The thin cartilaginous expansions from the sternum of the newt, prepared by the gold process, make very good specimens of hyaline cartilage. Thin sections may be cut by the microtome, or by hand. In this preparation the lymph canals will be seen looking like dark processes proceeding from the lacuna, in which the cell lies, into the hyaline matrix.

Sections of the nasal cartilages of small animals, growing bone, &c., will all give good examples of hyaline cartilage.

In the fresh state the cells will be seen to fill the lacunæ; but in hardened specimens they have all shunk, more or less, leaving a space.

Specimens of cartilage should also be hardened in chromic acid mixture, and thin sections stained with logwood.

FIBRO-CARTILAGE.

Make a longitudinal section of mouse's tail, and notice the intervertebral cartilage and its gradual transition into hyaline cartilage on the bone. The fibres will be seen in various aspects as they cross one another, and several sections should be examined; the cells will be seen lying between the fibres.

Make a section of the intervertebral disc of sheep

or ox, hardened in chromic acid mixture, and stain with logwood. Mount some sections whole and tease out others on the slide. Cover and examine. It will be difficult to make out the fibres in some sections.

ELASTIC CARTILAGE.

This can be well shown in the lobe of the ear or in the epiglottis. Procure the epiglottis of a sheep and harden it in the chromic acid mixture, cut sections and stain them with logwood.

The ear of a child prepared in the same manner, sections cut and stained with logwood.

The ear lobe of a pig also prepared in chromic acid mixture and stained with logwood. Sections of these must be thin and they must not be hardened too much or it will be difficult to cut them.

The pig's ear when well prepared makes a very useful specimen, as it shows a great many tissues.

BONE.

PREPARING HARD BONE.

Bone must be examined in two forms, first in its dry state, and secondly when it has been decalcified or had its earthy salts removed. In the case of dry bone a very few sections will suffice as it is a difficult and laborious task to get them well made.

The bone is fixed in a vice and sections as thin as possible are cut with a fine saw, these are rubbed