432 GENERAL ANATOMY. 



which this force is applied. The -same thing takes place in 

 paralysis determined artificially, by cutting all the nerves of 

 a member. In paralysis arising from cerebral affection, and 

 in contraction of the limbs, the attitude is sometimes different ; 

 the flexion being sometimes carried to a great extent. But 

 here arises a doubt, which is, whether the cause of paralysis 

 has been equally extended to all the nerves of the part; if in- 

 deed this cause does not originate in the tonic contraction of 

 some muscles. In the dead body the muscles remain contrac- 

 tile, and give a determinate attitude to all parts of the body, 

 until the cadaveric stiffness subsides. 



693. The muscles are possessed of sensibility, but only in 

 a moderate degree. In the state of health they produce little 

 more than the sense of fatigue during and after their action, 

 when it has been prolonged. When the action has been very 

 long continued and violent, it produces a painful sensation. 

 The same thing occurs in case of inflammation of their tissue 

 or of their cellular sheaths. Cabanis and Dr. Yelloly have 

 stated cases of diseases in which the muscles were insensible. 



694. The circumstances which manifest a continual change 

 of particles in muscular nutrition are not very evident; the 

 fact is nevertheless probable: it would seem to be the globu- 

 lar part of the blood that furnishes the materials for it. The 

 effects of exercise on nutrition, the augmentation and colora- 

 tion of the muscles, and the opposite effect of rest too long 

 continued, are well known. Paralysis produces an effect still 

 more remarkable on their diminution. The quantity and 

 quality of nourishment have a great influence on the volume 

 as well as strength of the muscles. Certain consumptive dis- 

 eases, such as phthisis, have a strong influence on muscular 

 atrophy. We are ignorant whether, in this case, there is a 

 diminution of volume only, or a disappearance of the fibres 

 altogether. 



695. In the embryo, the muscular tissue is not distinct 

 from the cellular tissue; they are confounded in a common 

 gelatinous mass. At a period but little remote from the mo- 

 ment of conception, the action of the heart presents a consi- 

 derable degree of development in the muscular tissue of that 



