44 



ELECTRO-PHYSIOLOGY 



CHAP. 



vidual segments of the fibril, accompanied by changes of refracti- 

 bility ; partly, however, to the sarcoplasm, which also undergoes 

 changes both in respect of local distribution and of refractibility. 

 Since the individual segments of the fibrils, or muscle-columns, 

 swell in different degrees, so that each element appears alter- 

 nately thickened and constricted (a form frequently observed by 

 Rollett in fresh, spontaneously contracting muscle-fibres), it is 

 evident that the sarcoplasm which separates the muscle-columns 

 ^^--^ ^ must be partially driven out of the 

 _^_^ z interstitial spaces of the swollen 

 sections, while it accumulates in the 

 interstices of the narrowed sections. 

 Remembering further that the sub- 

 stance of the fibrils (muscle-columns) 



x 7 



is clear in acid, swollen muscle, while 

 the sarcoplasm is dark (as in the 

 normal fibre with a high adjustment), 

 the explanation of the acid reaction 

 is very simple. 



The acid figures described corre- 

 spond (as Rollett shows) in all 

 essential points with the gold chlo- 

 ride figures, except that in the latter 

 the darker knots of sarcoplasm, as 

 well as the connecting lines, which 

 result from the impregnation of the 

 metal, are more or less intensely 



t with weak acid ; swelling of (Q) coloured, while the fibrillated Sub- 

 layers. (Rollett.) . , . , 



stance is unstained, so that the 



longitudinal section of the fibre gains considerably in clearness 

 and precision. 



Another kind of discoid disintegration (differing essentially 

 from the above) was first described by Bowman, and has recently 

 been reinvestigated by Rollett, in the muscles of insects. This 

 is a peculiar action of strong alcohol (93 %), in which the 

 muscles have been steeped for some time (twenty-four hours to 

 fourteen days). The figures obtained under these conditions are 

 very characteristic (Fig. 30). 



In fibres where the cross-striation corresponds with the simplest 

 schema (ZJQliQJZ\ the segments (QhQ) are found as trans- 







