76 CONTRACTILE ELEMENTS. 



No. 2 being more slightly elastic, or less resisting, than under 

 form No. 1. This singular phenomenon of a muscle which 

 lengthens while contracting proves, that what is called the 

 active state (form No. 2) has nothing to do with the shrink- 

 ing, and justifies the selection that we have made in using 

 the expressions, muscle under form No. 1 and No. 2, in 

 preference to speaking of contracted or retracted muscles. 



Thus, in form No. 2 the elasticity of the muscle is slight 

 and perfect, less even than under form No. 1. 



These propositions appear in singular contradiction to what 

 is commonly observed in that condition which we call a con- 

 tracted muscle, that is, one which has passed, or rather, is 

 passing, into form No. 2. Any one may prove for himself 

 that the biceps, for instance, when contracted is exceedingly 

 hard, and appears to be strongly elastic, that is, offering 

 great resistance when drawn out, so that we can hardly 

 believe in the softness of the muscle under the second form. 

 This is because, on account of their arrangement with regard 

 to the skeleton, the muscles in the living body hardly ever 

 attain the second form any more than the first (see above, 

 tonicity). When, for instance, the biceps passes into the 

 second form, it has a tendency to grow shorter by five-sixths 

 of its length; but the displacement which it may cause to 

 the bones allows it to shorten, at the most, by only one-sixth 

 or two-sixths; we have then a muscle of the second form, 

 forcibly drawn out, exactly like a strip of india-rubber 

 stretched violently ; it is necessarily, then, extremely hard and 

 resisting to the touch. This hardness is not caused by the 

 muscle being in the second form, but by this form being 

 forced, and not perfectly attained ; it does not arise from the 

 contraction of the muscle, but from the tension that it under- 

 goes during its contraction. This hardness is to the second 

 form what the so-called tonicity was, in a less degree, to the 

 first form. 



In order that a muscle may take the second form perfectly, 

 the bones must be disarticulated, or the muscle must be cut 

 at one of its insertions, after which it will be seen to shorten 

 considerably, at the same time growing broader (see Fig. 18, 

 p. 69). We have mentioned this already, when speaking of 

 the form of the muscles of the thigh, which are in a state of 

 tetanus after amputation. Being then subjected to traction, 

 the muscle hardens, and as the forcible elongation increases 

 the resistance becomes greater, exactly as with a strip of 

 india-rubber. Let this elongation be caused by the relation 



