288 SPECIAL HISTOLOGY. 



and, in fact, the greater the degree of degeneration, the more 

 distinctly is this structure exhibited. The muscular fibrils, in 

 fresh muscles, are constantly visible only in a transverse 

 section, and in the thoracic muscles of insects, elsewhere it is 

 true they are occasionally seen, but more by chance than other- 

 wise. They are easily isolated artificially in preparations pre- 

 served in spirit, particularly in the perennibranchiate Reptiles 

 (Siredon, Proteus, &c), by treatment with chromic acid 

 (Hannover), by maceration for from 8 to 21 days, at a tem- 

 perature of 1 — 8° R. in water, to which, for the prevention 

 of putrefaction, some corrosive sublimate has been added 

 (Schwann) ; maceration also in the fluids of the mouth (Henle) 

 allows of their being readily exhibited; whilst, according to 

 Frerichs (Wagner, 'Handworterb./ Til, 1, p. 814), in the 

 stomach, the fasciculi break up into Bowman's discs. The 

 nuclei of the fasciculi are best studied under the application of 

 acetic acid ; by soda (vide supra) they may be isolated, and by 

 potass be made to swell considerably (Donders). On the 

 subject of the effect of various reagents on the elementary 

 tissues of muscle, the treatises of Donders (Holland. 'Beitrage') 

 and Paulsen ('Observ. microchem.,' Dorpat, 1849) may be 

 consulted. The vessels of muscle are studied in fresh, thin 

 muscles, and in injected preparations ; the nerves in the 

 smallest human muscles, in the muscles of the smaller Mam- 

 malia, in the cutaneous muscle on the thorax of the Frog, with 

 or without the addition of soda. The perimysium, and the 

 form and position of the muscular fibres, are very well shown 

 in transverse sections of half-dried muscles ; and the same 

 observation holds good with respect to the elementary tissues 

 of the tendons. The insertions of the latter into the bones, and 

 their cartilage-cells in those situations are readily seen; in the 

 tendo Achillis, for instance, in vertical sections of dried pre- 

 parations ; with respect to their relation to the muscular 

 fasciculi, vide supra, § 81. In order to examine the cartilage- 

 cells in tendons, thin horizontal sections are taken from the 

 surface, which are treated with acetic acid, or a very dilute 

 solution of soda. For the study of the development of muscle, 

 the naked Amphibia must be placed in the first rank, and the 

 Mammalia only in the second.] 



Literature. — Besides the memoirs, cited in § 27, there are 



