In preparing this edition I have endeavoured to meet the requirements of students, and of practitioners who desire to keep up their histological work. Those methods are selected which have been found to work well in practice, and it has been thought better to describe a few in detail rather than give a short account of many similar methods. I have again to express my obligation to the various instrument makers for the illustrations of microtomes, &c.; to Dr. Fearnley, of Bradford, for th

Probably there is nothing more perplexing to a beginner than to decide what apparatus is required. If he consult a price list, it is difficult for him to tell which articles will be necessary, and which will be either luxuries, or required only for special investigation. In the following account of requisites, those only will be described which it is useful to have always at hand. They will be found sufficient for ordinary work, but for special investigations a more elaborate equipment will be r

For the satisfactory examination of tissues it is necessary that they should be “hardened” in certain fluids. The object of this is to give the specimens greater consistence, so that thin sections may be more readily obtained and more safely manipulated, and also to “fix” the tissue element as far as possible in the same relative position as in the living body. The hardening process also acts on the protoplasm of the cells, and prevents their swelling up when placed in water, and in the various

1. Alcohol. 2. Flemming’s solution (modified by Friedmann) :— Small pieces should be hardened in this fluid for twelve to twenty-four hours, and then washed and transferred to alcohol for some days before staining. 3. Nitric acid. —A ten per cent. solution in distilled water. It hardens the tissue in three to four hours, and should be followed by 70 per cent. alcohol, the hardening being completed in absolute alcohol. In using any of these methods it is necessary that the tissue be removed from

Used in the preparation of bone, tooth, osseous tumours, &c. The two best fluids for general use are:— Chromic and nitric fluid. —This is made as follows:— If the bone is not very compact the fluid may be used diluted with an equal quantity of water. A large quantity of fluid should be used, and like all decalcifying fluids, it should be frequently changed. As soon as the specimen is sufficiently flexible, it should be thoroughly washed in running water for some hours, and then transferr

Embedding of sections. —Before sections are made the tissues require to be embedded in some fluid, which will permeate their interstices, and is capable of being rendered firm so as to support the most delicate parts when the knife passes through the tissue. The most generally useful substances are:— (1) gum, (2) celloidin, (3) paraffin or wax. Gum. — Picked colourless gum arabic 2 parts, cold water 3 parts. Leave with frequent stirring until dissolved. Add ten drops of carbolic acid to each oun

1. By flotation . In this method the section whether stained or unstained is placed in a bowl of water, or normal salt solution (p.  53 ). A clean slide is then introduced into the water at an angle of about 60°, a little more than half of its length being submerged. The section is then brought up by the needle and floated as far as possible into position on the slide. One corner is then fixed by the needle, and on gently withdrawing the slide the section should lie flat. If any folds are left n

Farrant’s solution :— In making this solution the best gum arabic must be used, and only the clearest pieces of this. “Powdered gum acacia” should be avoided, as though it looks white it often yields a brown mucilage, and besides is frequently adulterated with starch, &c. The glycerine and water should be mixed and the gum arabic added. The mixture should be allowed to stand for some weeks, with frequent stirring until the whole of the gum is dissolved. Then allow it to stand for a week

Much information may be obtained from unstained sections, and in most cases one section should be examined unstained, but the specimens mounted in this way are so transparent that it is difficult to study the details of the tissue. They are therefore usually prepared by treating them with some staining reagent, not merely to render them less transparent, but also to “differentiate” the elements of the section, by staining one part more deeply than another, or of a different colour. Thus hæmatoxy

1. For staining nerve fibres . Three methods (two of which are modifications of the first) are employed far more often than any others. By these methods the myelin coating is stained. Tissues must have been hardened previously for many weeks in Müller’s fluid, or some other bichromate solution. They are then overstained in a solution of hæmatoxyline, and the section treated with a suitable bleaching reagent, when the colour is discharged from all the tissue elements except the nerve fibres. This

It is impossible, within the limits of this work, to attempt any adequate description of the modern methods of bacteriological investigation. Some of these are very lengthy and complicated, and require much skill and practice before good results can be relied on. But those who do not desire to make a special study of bacteriology may often require to examine for the presence of organisms in sections, or in various excretions, and it is hoped that they may find the following short description of

In all these methods blood is obtained by pricking the skin of one of the fingers, or the lobule of the ear, preferably the latter. The skin must previously be washed with soap and water or ether, to remove any grease or epithelial scales. The puncture should be made firmly so that blood may escape freely. The finger or ear must not be squeezed. Specimens must be made rapidly before red corpuscles have run into rouleaux. The slides and coverslips employed must be scrupulously clean, or it is imp

Fresh blood may be stained by mixing with Ferrier’s fuchsine solution:— Dissolve and add A spot of this solution is mixed with the blood on a slide by means of a mounted needle, and covered with a clean cover-glass. The red corpuscles are slightly stained, while the nuclei of the white corpuscles are stained a bright crimson, and the “blood plates” a deep pink colour. Stained preparations may also be obtained by using Toison’s fluid , which serves also for diluting the blood in order to determin

Injection of blood vessels may be performed on small animals, or on individual human organs after removal from the body. The object is to fill the vessels with a coloured fluid which will solidify afterwards. It is possible in the same organ to inject the arteries with a red medium, the veins blue, and secretory ducts, such as bile ducts, yellow or blue. The most convenient basis for an injection mass is gelatine, as its solutions liquefy at a temperature of about 100° F., and solidify a little

Normal histology. —It cannot be too strongly impressed on the beginner that a thorough mastery of the normal appearances of tissues and organs is absolutely necessary before attempting to make an accurate study of morbid changes in them. He should not be satisfied with examining one specimen of an organ but as many as he conveniently can, in order to be fully acquainted with the many deviations from normal which may exist without actual disease. He should therefore obtain several animals, such a

Methods in Microscopical Anatomy— Whitman . Practical Pathology— Woodhead . Textbook of Bacteriology— Crookshank . Manual for Physiological Laboratory— Harris and Power . Practical Histology— Fearnley . Practical Pathology and Histology— Gibbes . Journal of Microscopical Society. Methods and Formulæ— Squire . The Human Brain— Goodall . Practical Bacteriology— Kanthack and Drysdale . Methods of Microscopical Research— Cole . Abbe’s condenser, 11 Absolute alcohol, 21 Acetate of copper, 89 Air bubb