250 William Christopher Krauss 



the back and extensors of the thigh, some contractures, and a 

 peculiar difficulty in rising from the ground. Repeated ex- 

 aminations of the nerves and cord have been unsuccessful, and 

 hence the inference that the muscle itself is the seat of the 

 lesion, although the notion is gaining ground that the real 

 lesion may be located in the nerve centers, perhaps in the 

 spinal cord. 



To understand better the pathological changes occurring in 

 the muscles, it may be desirable to review brieflj' the histology 

 of a muscular fiber. A striated muscle is composed of a num- 

 ber of bundles, surrounded bj^ a layer of areolar tissue, the 

 external perimysium. Each bundle or fasiculus, enveloped 

 by a thin, delicate membrane, the internal perimysium, is 

 composed of bundles of fibres, separated from each other by 

 a delicate connective tissue, the endomysium. These fibers 

 are arranged parallel to each other, are from two to four centi- 

 meters in length, and are united either to the tendons or apo- 

 neuroses, or else connected with the adjacent fibers. 



Each fiber is composed of a number of filaments or fibrillse, 

 inclosed in a transparent homogenous membrane, designated 

 by Bowman, the sarcolemma. In the mammalia, elongated 

 nuclei are present on the internal surface of this membrane. 

 The primitive fibers are cylindrical or prismatic in form, 

 about sixty -five microus in breadth, and their length 

 depends not so much on the length of the muscle, as upon the 

 arrangement of the tendons. They are marked by transverse 

 and longitudinal lines or striae, giving them a characteristic, 

 striated or striped appearance. I will not take up the histo- 

 logy of the primitive fibrillas, but will limit myself to the 

 primitive fiber. (See Plate, fig. i). 



Each fiber has a vascular and nervous supply, the former 

 being furnished by the ramifications of the capillaries, run- 

 ning parallel between the fibers. The nervous supply is from 

 the moter nerves, and their termination in the muscle has 

 been the subject of much controversy. The motorial end- 

 plates of Kiihne or nerve hillocks of Doyere are generally 

 recognized by most recent observers. The nerve terminates 

 below the sarcolemma, where the medullary sheath becomes 



