MUSCULAR TISSUE. 



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the body, certain peculiar, but I venture to think, non-vital 

 properties. Now, the same observations that I made with 

 regard to the continuity between the bioplasm and formed 

 material of cartilage, tendon, and elastic tissue, apply to 

 this more elaborate and highly endowed tissue, which can 

 always be shown to be continuous with the bioplasm, espe- 

 cially in the case of young and rapidly growing muscular 

 fibres. Not only so. but in certain cases at the outer 

 part of a very fine muscular fibre a certain portion of soft 

 material is to be discerned, in which no structure what- 

 ever can be demonstrated. This is found to pass into a 

 thin fibre, requiring very high magnifying powers in order 

 to demonstrate it satisfactorily, but with care it may be 

 followed uninterruptedly into the contractile muscular tissue. 

 There is reason for believing that during the formation of 

 muscular tissue the bioplasts are continually moving that 

 the entire "nucleus," so to say, moves, and that as it 

 moves it leaves this material, which gradually becomes 

 muscular tissue, behind it. At one time I believe the 

 "nucleus," or mass of bioplasm, or living matter, repre- 

 sented in fig. 4, PI. VIII, occupied, for example, the 

 position between b and c, instead of that between a and b; 

 but it has moved in the direction of the arrow, and as it 

 has moved the most posterior portion of it has undergone 

 a change, and become converted into ordinary contractile 

 muscular tissue. I believe that it is in this simple way that 

 muscular tissue is formed, and 1 believe that the material 

 which exhibits the so-called " vital" contractility bears 

 precisely the same relation to the nucleus or mass of 

 bioplasm as the so-called cell-wall of a common cell bears 

 to its "nucleus" or bioplasm. Contractility is not a vital 



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