CONTRACTILITY AND VITAL MOVEMENTS. 213 



muscle is the same substance, or even closely allied 

 to the matter constituting the moving matter of any 

 form of bioplasm. The bioplasm (nucleus) of muscle, 

 its movements during the formation of muscular 

 tissue, and the tissue or formed material produced by 

 it, are represented in Plate IV, fig. 3, page 217. 



258. Contractility and vital movements. The doc- 

 trine that living matter and the contracting material 

 of muscle are composed of the same substance, in the 

 present state of knowledge, is untenable, and any one 

 who examines muscle contracting, and compares the 

 action with that of the living matter of an amoeba, a 

 white blood-corpuscle or a pus-corpuscle undergoing 

 its varied and very remarkable movements, will feel 

 quite convinced that movements, differing from one 

 another in so many respects, cannot be due to one and 

 the same property; nor will those who have actually 

 studied the phenomenon be inclined to class the latter, 

 which have been shown to be vital movements, in the 

 same category as movements referred to " contrac- 

 tility." It must be obvious to any one who con- 

 siders the question, after having carefully observed 

 the facts, that muscular contraction is a mere alterna- 

 tion of movement, limited in direction as well as 

 regards the degree of change. On the other hand, a 

 mass of bioplasm may move in any direction what- 

 ever, and there is no limit to its movements. So 

 varied are the vital movements of living matter, that 

 the same mass probably never twice in its life assumes 

 the same form. Moreover, the living matter may move 

 itself in its entirety from one place to another, while 

 a portion of contractile tissue can only become short- 

 ened and lengthened, but it must remain in the same 

 place. In the first case one portion may move 

 in advance of another portion, and in any direction, 

 while in the contractile tissue, although one part may 

 move in a direct line to or from another part, it is not 

 possible for any particle to get before, or place itself 



