CHAPTER VIII. 



COMMENTARY ON BEALE'S MUSCLE THEORY. 



ON entering on the question of the structure and 

 function of the muscles, let us first give a short 

 summary of Dr. Beale's views : 



The transverse markings of the striped muscle, which is the 

 most perfect form of this tissue, have long been objects of 

 attention, but they are not essential to contractility, for they 

 are absent in the involuntary muscular fibres. In the early 

 stage of development of the voluntary muscles, they are also 

 absent, and Dr. Beale states that they do not appear till the 

 act of contraction has occurred repeatedly ; and he considers 

 they are due to important changes taking place while the con- 

 tractile material is in a soft and plastic state. In opposition to 

 the prevalent theory, that muscular movements are the off- 

 spring of the protoplasmic movements, Dr. Beale shows that 

 the two kinds of movement are essentially different. Accord- 

 ing to him " a contractile tissue may be likened to a chain of 

 beads, every bead being capable of becoming short and broad, 

 or long and narrow, but forced to retain its relative position 

 with regard to every other bead. The contractile cord may 

 thus become shorter, causing its points of attachment to ap- 

 proximate" ("Biopl.," p. 214). And he defines a contractile 

 tissue to be one " in which simple movements, like shortening 

 and lengthening, alternate with one another, each movement 



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