KINE TO GENE SIS. 2 5 1 



Hitter, 1 a distinguished specialist in the diseases of 

 the joints, gives the following positive information as 

 to the easy formation of new modifications of muscu- 

 lar structure : 



" Muscular tissue everywhere possesses the capa- 

 city to shorten itself in consequence of continued ap- 

 proximation of its points of insertion ; that is, to be- 

 come shorter by the disappearance of tissue, in pro- 

 portion to the duration of the approximation. This 

 law is of the greatest importance for the muscular con- 

 traction of joints, that is, for such restriction of the 

 freedom of movement of the articulations as has its 

 origin in muscular movements. We have experimen- 

 tal opportunities for the observation of this fact, such 

 as the effect of a stiff bandage on an articulation. When 

 it is necessary, in consequence of a fracture of the fore- 

 arm, to fix the elbow-joint for several weeks in a right- 

 angled flexure, we find on the removal of the bandage 

 that the power of extension of the fore-arm has been 

 much restricted. That the cause is nutritive change 

 is proven by the fact that considerable force of mus- 

 cular contraction is necessary before the normal ex- 

 tension can be effected." 



Similar phenomena are to be observed in conse- 

 quence of a prolonged lying in bed, where no injury 

 to the innervation exists. 



"The muscles adapt themselves to the permanent 

 positions of the articulations, as in joint-contractions 

 which are due to muscular paralysis. Those muscles 

 which are habitually stretched, increase in length, 

 while those whose insertions are approximated, are 

 shortened, producing joint-contraction." He then goes 



1 Hitter, " Studien an den Extremitfitengelenken Neugeborener und Er- 

 wachsener." Virchow's Archiv fUr pathologische Anatomic, Bd. XXV., 6-8. 



