LECT. XVI. 



CONTRACTION PARTIAL. 



299 



Fig. 22. 



taken place in the height of the column of the liquid, 

 which is precisely the same now, that it was before the 

 contractions. 



Structure of Muscular Fibre. According to the observa- 

 tions of modern micogrophers, it appears, that muscular 

 fibre is composed of a great number of cells or globules 

 (discs) arranged in piles, according to the longitudinal di- 

 rection of the fibres ; and that from the union of these 

 piles muscular fasciculi are formed ; so that a muscle ap- 

 pears to be susceptible of a kind of cleavage, 

 both longitudinally and transversely. This 

 structure has, therefore, a great analogy with 

 that of the electric organs of fishes ; and it is 

 very remarkable that, with respect to the gene- 

 ral circumstances of the two phenomena, the 

 same laws preside over the discharge of elec- 

 tric fishes and muscular contraction. 



In the act of contraction, the globules, or, 

 to speak more accurately, the transverse striae 

 of muscular fibres, approach one another ; the 

 distances between them diminish, and the 

 thickness of the fibres augments : hence the 

 volume of the muscle remains sensibly the 

 same. 



Contraction partial. Bowman states, that 

 active contraction never occurs in the whole 

 of an elementary muscular fibre at once ; but, suture of the 



,. .. . ... _ ' ultimate fibrillffi of 



according to this skilful anatomist, the con- striated muscular 

 traction is partial, and is propagated during fibre ;-. a fibril 



, , ,, in a state of ordi- 



a certain very short, but yet appreciable inter- n a ry relaxation ; j, 

 val of time ; so that in a fibre in a state of a fibril in a 8tale 



, , of partial contrac- 



contraction, there must be some points at rest, ti on. 

 and others brought nearer together. 



I am inclined to think that these appearances exist only 



