412 ^ENERAL ANATOMY. 



the fleshy columns of the ventricles of the heart, the longitu- 

 dinal bands of the colon, &c. There are, on the other hand, 

 many of the muscles which scarcely equal a small portion of 

 a bundle of which the preceding are composed, and which are 

 not formed of distinct bundles. 



The muscular bundles are themselves formed of bundles less 

 voluminous, and these latter of others still more minute, which 

 may be distinguished in almost all the muscles. 



656. All the muscles may moreover be divided into fasci- 

 culi or fibres visible to the eye, fasciculse sen Jibrse secunda- 

 rise. These fasciculi, the ultimate degree of division percep- 

 tible to the naked eye, have, in all the muscles, nearly the 

 same form and the same thickness. They may, according to 

 the preceding divisions, be perceived by a longitudinal dis- 

 section, but still better by a traverse section, and especially in 

 a muscle boiled or steeped in alcohol. They have a prismatic, 

 pentagon or hexagon form, and never a cylindrical one; their 

 diameter varies a little; their length, according to Prochaska, 

 is equal to the entire extent of the interval between their two 

 attachments, even in the sartorius muscle. Haller, on the 

 contrary, thought with Albinus, that the fibres or the fasciculi 

 were not so long as the muscles, and that fasciculi of fibres 

 terminated by tapering off in the intervals of other similar 

 parts; this does not appear to be the case. 



657. The muscular fibres, Jibrse musculares primarise y 

 seufila carnia, visible only by the aid of the microscope, are 

 the ultimate degree of anatomical analysis of the muscles. 

 We are indebted to Hooke, R. Leuwenhoeck, Dehayde,Muys, 

 De la Torre, Prochaska, Wenzell, (Brothers,) M. Autenrieth, 

 M. Sprengel, Messrs. Ed. Home and Bauer,* and to Messrs. 

 Prevost and Dumas,t for the best observations on this subject. 

 It must be remarked, however, that the first of these observers 

 having in their researches only made use of lenses which mag- 

 nified about 150 times, were not enabled to perceive the pri- 



* Croonian Lecture, in Philos. Trans, ann. 1818. 



f Examcn du sang el de sm action dans les divers Phenomenes de la J r ic; 

 in Annalts de chimie et de Phys. t. xxii. 



