92 



CONTRACTILE ELEMENTS. 



change in length of the muscle, but of its change in thick- 

 ness, by enclosing it in a kind of pincers, one of the movable 

 branches of which (myographical pincers, Marey) operates 

 on a registering apparatus. Of course, we find the same 

 simple shocks, or elementary contractions, and the same fusion 

 of these shocks in physiological tetanus, as with the former 

 method, but the process is more practical, and may be made 

 use of, for instance, to register the contractions of the biceps 

 in man. 



in. SMOOTH MUSCLES. 



THE smooth muscular fibres (Fig. 21) are situated chiefly 

 in the coats of the viscera (intestine, bladder, uterus, etc.), 

 or in the tubes which open into or proceed from them 



(the bronchus, ureters, 

 urethra, bile duct, etc.). 

 It is thus difficult to form 

 a distinct group of this 



'ff/rfiJilll contract ^ e element, for 

 //IW.illl the purpose of making it 

 a special study. 



Still, by studying the 

 smooth muscles as we 

 find them with all the 

 normal intricacies of their 

 fibres, we are easily con- 

 vinced that these ele- 

 ments, like the striated 

 fibre, possess the property 

 of appearing under two 

 different forms, which we 



Smooth muscles (rffcl wall of the bladder)* mav ? tU1 Cal1 fi rst and 



second. 



The smooth muscle appears to possess, under these two 

 forms, the same properties as the striated muscle under 

 similar forms, as well in regard to its chemical reactions, as to 



scope, the reader is referred to a monograph by Professor 

 Thomas Dwight, Jr. (Boston Nat. Hist. Soc. Proceedings, Nov. 

 5, 1873.) 



* A, A fasciculus, from which proceed, in a, a, detached cell fibres, b, Repre- 

 sents it in section. B, A similar fasciculus, having been exposed to the action 

 of acetic acid : the nuclei appear long and slender, a and b, as above. 300 diam. 

 (Virchow, Pathologic Cellulaire.) 



