The enamel is dissolved by decalcifying fluids. To study it a specimen of unsoftened tooth should be made, according to the directions given for bone.
Striped muscle.—Should be studied in various animals.
The leg of an insect such as a cockroach may be hardened in osmic acid. One leg should be hardened in a straight position so as to fix the fibrils in the fully extended position, another should be bent up so as to get specimens of relaxed fibrils.
Portions of muscle should be removed, and teased on a glass slide in some staining fluid such as picrocarmine, a tenth per cent. solution of eosine or quarter per cent. of safranine.
Sections of amphibian and mammalian muscle should be prepared to show their differences in structure. The most convenient part to select is the tongue, as a view of the fibres is obtained both in longitudinal and transverse sections. Sections should be stained in eosine and hæmatoxyline which gives a beautiful effect. For special stains for intra-muscular nerve endings see page [92].
Heart muscle.—A portion should be teased fresh in picrocarmine or eosine, another portion hardened in Müller’s fluid, and sections made and stained with eosine and hæmatoxyline.
Unstriped muscle may be obtained by teasing a fresh portion of the muscular coat of the small intestine of an animal, or by sections of the hardened intestine, bladder or uterus. Stain in picrocarmine or preferably eosine and hæmatoxyline.
Nerves.—The special methods for staining nerve tissues are detailed in Chapter [VI]. The student must remember that the ordinary staining methods are also applicable to nervous tissues.