THE MUSCULAR SYSTEM. 277 



whether this depend upon the growth of the pre-existing mus- 

 cular fasciculi, or on the introduction of new ones — the latter 

 of which suppositions may perhaps be affirmed without much 

 chance of error, in the case of the extreme degrees of patho- 

 logical hypertrophy. Atrophy of the muscles is very frequent, 

 as in old age, paralysis, particularly of the tongue, and in 

 cases of lead-poisoning, and in the development of cancer, 

 fibrous tumours (consequent on inflammation), and of fat, &c. 

 in the substance of the muscles. The processes, however, 

 which are set up in these cases, have as yet been but little 

 investigated. In extreme old age I find the fasciculi small, pre- 

 senting occasionally a diameter of not more than 0-001 — 

 0008'", easily broken up, mostly without transverse stripes, and 

 with the fibrils indistinct, whilst they frequently contain yel- 

 lowish or brown granules, as much as O'OOl'" in size, often in 

 large quantity, and very many vesicular nuclei with nucleoli. 

 The nuclei often form continuous rows, or are accumulated 

 on the inner surface of the sarcolemma, exhibiting in a peculiar 

 manner the same distinct indications of an energetic mul- 

 tiplication by endogenous formation, as are presented in the 

 embryo (vide this §, supra). In fatty degeneration, the 

 muscular fasciculi are, by degrees, replaced by connective tissue 

 and fat cells which are developed between them; whilst, at the 

 same time, minute fatty molecules are developed in great 

 number within them, in place of the fibrils, which gradually 

 disappear. 



Paralysed muscles were found by Reid ( f On the relation 

 between Muscular Contractility and the Nervous System/ 

 'Edinburgh Monthly Journal of Med./ 1841) to be thinner, 

 softer, and paler; and Valentin ("Phys./ 2 ed. 2 Th., p. 02), 

 noticed in such cases that the transverse stripes were indistinct, 

 or had disappeared, and could no longer be produced by water, 

 alcohol, &c. ; the longitudinal stripes existed, but did not 

 present their usual aspect, more resembling those of macerated 

 muscle. Subsequently the altered fasciculi disappeared in 

 part, and were to some extent replaced by fat. In a case of 

 atrophy of the pectoralis major caused by cancer, I noticed 

 conditions similar to those I had observed in old age, viz. : 

 destruction of the fibrils, the development of brownish granules, 

 and the presence of numerous nuclei, together with a clear fluid 



