By the aid of the handy little spring clip (Fig. 239), objects of delicacy when mounted may be left to dry and harden for any length of time. [Illustration: Fig. 239.--Spring-clip for Mounting.] _Striped muscular fibre_, taken from the pig, must be teased out in a two per cent. solution of bichromate of potash, in which it should remain for two or three weeks, when it may be transferred to methylated spirit, and allowed to remain until required for mounting. Soak a piece in water to remove the spirit, place a small fragment on a slide in a few drops of water, and with a couple of needles tease the tissue up, so as to separate the fibres. Drain away the water, and apply a drop or two of Farrant’s medium and a cover-glass, which cement down as before directed. _Fibrous tissue_ may be served in the same way. _Yellow elastic tissue_ must be first placed in a solution of chromic acid and spirit for ten days, and then treated as directed for muscular fibre. _Non-striated Muscle._--A piece of the intestine of a rabbit should be steeped in chromic acid and spirit for ten days, then washed in water; strip off a thin layer of the muscular coat, and stain in hæmatoxylin solution. Well wash in ordinary water until the colour changes to blue, when it will be fit for mounting. Place a fragment on a slide and a drop of water, and carefully separate the fibres with a pair of needles. Drain off the water, as it is now ready for mounting, place on slide, and add a drop or two of Farrant’s medium, and place on the cover-glass. _Nerve Tissue._--Dissect out the large sciatic nerve from a frog’s thigh, and stretch it on a small piece of wood, to which pin both ends of the nerve, and transfer it to a one per cent. solution of osmic acid for an hour or two. Wash in distilled water; tease up a small fragment on a slide (as shown in Fig. 240), and apply a drop or two of Farrant’s solution and cover-glass. Tissues containing air should be soaked in water that has been boiled for ten minutes; this will displace the air. (For Farrant’s medium, see Appendix.) _Glycerine Jelly._--Dissolve one ounce of French gelatine in six ounces of distilled water, and melt together in a hot-water bath. When quite dissolved, add four ounces of glycerine, and a few drops of creosote or carbolic acid. Filter through white filtering paper while warm, and keep in a capped bottle. This may be used instead of Farrant’s solution. [Illustration: Fig. 240.--Method of Teasing out Tissue.] _Nitrate of silver_ darkens by exposure; it is used in a half per cent. watery solution. Specimens to be acted upon should be washed in distilled water, to remove every trace of sodium chloride, and then steeped in the silver solution for some two or three minutes, after which they should be again washed until they cease to turn milky; then place them in glycerine and expose them to the action of light until they assume a dark brown colour, when they should be mounted in glycerine or glycerine jelly.