1 44 



MUSCULAR SYSTEM. 



[sect. 78. 



Fig. 65. 



liymenoptera, lepidoptera, diptera, ortlioptera in part, Tvemiptera in part), the 

 individual fibrils can be very beautifully separated. Considering the great 

 similarity between the muscles of insects and those of 

 the higher animals, in all other essential points, the 

 above fact appears to me to be very striking. I am, there- 

 fore, for this and the other reasons assigned, fully con- 

 vinced of the existence of fibrils during life, and believe 

 that, in man and many animals where they cannot be so 

 easily isolated, they are held together by an intermediate 

 substance, and, in fact, so firmly, that, under certain 

 circumstances, fissures may take place across the fibres, 

 i.e., in the direction of the thinner parts of the fibrils. 



I consider the sarcous elements as artificial products, 

 occasioned by the breaking up of the fibrils at the parts 

 where they are thinner, which naturally takes place much 

 easier there than elsewhere. I refrain from giving an 

 opinion as to the nature of these particles, as I hold that 

 our microscopes do not afford adequate data for forming a 

 sure judgment respecting elements of such fineness. 



A. a muscular fibre, 

 or primitive fascicu- 

 lus, breaking up in 

 the transverse direc- 

 tion, into discs, 350 

 times magnified. It 

 exhibits distinct trans- 

 verse and fainter lon- 

 gitudinal strife. The 

 discs, of which B. re- 

 presents one more 

 magnified, are granu- 

 lated, and consist of 

 the sarcous elements 

 of Bowman, or, ac- 

 cording to other au- 

 thors, of small pieces 

 of the fibrils. After 

 Bowman. 



§ 78. The muscular fibres, in the trunk and 

 extremities, are generally so connected, that, 

 without dividing and reticularly uniting, but ter- 

 minating not unfrequently here and there in the 

 interior of the muscles with pointed extremities 

 (Eollet), they lie parallel to each other in pris- 

 matic bundles, extending the whole length of the 

 muscle. Each of these so-called secondary fasciculi 

 is enclosed by a special investment of connective 

 tissue. Several of these are united by stronger investments, to 

 form tertiary fasciculi; while, finally, a greater or smaller number 



of these last combine to form the 

 bellies of the muscles and muscles 

 themselves. 



The muscular fasciculi may be so 

 arranged as to give rise to mem- 

 braniform muscles, which are ex- 

 tended in the superficial dimension; 

 or they may form the oblong or 

 fascicular muscles, in which they 

 are collected into thicker masses. 

 Accordingly, the muscles are aggre- 

 gations of many larger and smaller 



Transverse section from the sterno-mas- g«wuuo vm. j & 



toid in man, 50 times magnified, a. external secon ^ arl i and tertiary bundles, whose 



perimysium; 6. internal perimysium; c. sow/ii™^"""^ y ; 



primitive and secondary fasciculi. 



