352 MUSCLES* 



being estimated at the two-thousanth part, or less, of an inch* 

 Such minute observations are necessarily very uncertain. 



In meat which is prepared for the table by roasting or boil- 

 ing, or in a muscle which is contracted, one frequently sees 

 the fibres undulated or crooked. By Prochaska it is attributed 

 to the bridling of the fibre, by the contraction of its cellular 

 substance, nerves, and blood vessels. The cause, however, i 

 not well ascertained : the condition seems to be one of the pe- 

 culiarities of muscular fibre, which it manifests when in a state 

 of contraction only; for it disappears whenever the fibre is re- 

 laxed, either by spontaneous movement, or by stretching it in 

 the dead body. This undulation has probably contributed to 

 the many inexact observations on the structure of muscles. 

 Thus, Haller thought they consisted in a series of ovoid vesi- 

 cles, which lengthened in a state of relaxation, and became 

 more globular in a state of contraction. It is unnecessary to 

 dwell on mere errors of the eyes or of the imagination, for the 

 fact seems to be now well established, that, though the muscu- 

 lar fibre, by contracting, loses its straightness and becomes 

 crooked, yet this is effected without change in the form of the 

 ultimate globules of which it consists. 



By some it has been asserted that muscles are only the con- 

 tinuation of blood vessels. To this it is replied,* that though 

 insects have muscles, yet they have not blood vessels, so that 

 the former cannot be a continuation of the latter. Moreover, 

 a successful injection, though it may penetrate very finely be- 

 tween the fibres, so as to cause the muscle to swell considera- 

 bly, yet none of these vessels can be traced into the ultimate 

 fibre. The vital phenomena and the organization of muscular 

 fibre, are so very different from cellular substance, from nerves, 

 and from vessels, that it cannot be less than a distinct struc- 

 ture. 



Notwithstanding this limitation, which is put upon the dis- 

 tribution of the blood vessels, every muscle is abundantly sup- 

 plied by them. The arteries come from the adjacent large 

 trunks, and penetrate at different points of the periphery of the 

 muscle. They first of all pass between the larger fasciculi and 



* Beclard, Anat. Gen. 



