EXAMINATION OF THE MUSCULAR SYSTEM. 655 



may be sometimes employed with advantage by a practised 

 hand." 



Nerves. — The structure and arrangement of nerve-fibres are 

 best studied in the mesentery of small animals, as the newt ; 

 though with a little care in manipulation they can be very well 

 displayed in any part of the nervous system. Their ultimate 

 distribution, however, presents greater difficulties. Phosphoric 

 acid, and solutions of caustic soda, and iodine of different 

 strengths, are of great use in rendering these fibres more dis- 

 tinct. According to Dr. Waller, the tongue of the frog is best 

 adapted for examining the arrangement of nerve-fibres in papillae. 

 When the nerve-fibres are not quite fresh, or have been soaked 

 in water, and where they have been stretched or subjected 

 to pressure for some time, their structure will be found to have 

 undergone certain peculiar changes, as complete conversion into 

 fibrous tissue, fatty degeneration, &c. (Fig. 348.) 



EXAMINATION OP THE MUSCULAR SYSTEM. 



Muscular Fibre. — Sareolemma. — Muscular fibre is of two kinds, 

 — the striated, voluntary, or muscular fibre of animal life ; and 

 the unstriated, involuntary, or muscular fibre of organic life. 



The voluntary muscles of man and the lower animals furnish 

 specimens of the striated fibre. They may be prepared for 

 examination by cutting out a small slice from a muscle, sepa- 

 rating the fibres with fine needles, and placing them upon a glass 

 slide, and adding a drop or two of water. Muscles which have 

 been boiled or hardened in chromic acid, corrosive sublimate, or 

 spirits of wine, yield excellent sections for examination. The 

 general anatomy of voluntary muscular fibre is well displayed 

 in the thin slips of muscle lying just beneath the skin of small 

 animals, as the frog; while the general arrangement and form 

 of the fibres is well shown, according to Beale, in a transverse 

 section of the pectoral muscle of a teal (Querquedula creeca), 

 which has been put upon the stretch, and allowed to liecome 

 perfectly diy. 



The ultimate fibrillae may be studied with advantage upon the 

 muscular tissue of the eel and pig. The fibrillse are separated 

 and rendered distinct by maceration in chromic acid. From the 

 back of the throat, after a meal of meat, in the discharges of 

 cholera patients and in vomited matters, admirable specimens, 

 showing the transverse striae, may often be obtained. In 

 examining the arrangement of the nuclei, solutions of caustic 

 soda and acetic acid will be found very useful. 



In the tongue of the frog, as shown by Kolliker, and in the 

 upper lip of the rat, according to Huxley, peculiar fibres, known 

 as branched muscular fibres, may be found. To obtain specimens 

 of these fibres, the tongue of a frog is boiled for a short time in 

 water. A piece of the mucous membrane is then dissected away, 



