464 



GENERAL PHYSIOLOGY 



fatigued specimens only Dobie's line was to be seen clearly, [and 

 the whole contents of the segments stained uniformly without any 

 differentiation of the discs being noticeable (Fig. 239). But the 

 granules, or sarcosnmes, lying in the sarcoplasm between the 



Fig. 238. — Curve of tetanus of a fatigued muscle of a frog. 



individual fibrillse were enormously enlarged in the fatigued, in 

 comparison with the resting, muscle. It would lead us too far to 

 consider in detail the significance of these changes. Hodge ('92), 

 G. Mann ('94), and Lugaro ('95), have recently made known distinct 

 microscopic phenomena of fatigue in the ganglion-cells of mammals, 



A B 



Fig. 'J31I. — Wing-muscles of a blue-bottle fly (Musca romitoi-ia). A, At rest; £, fatigued. The 

 division of the muscle-segments into discs has become invisible and the sarcosomes between 

 the fibrillaj are enormously enlarged. (After H. M. Bernard.) 



birrls, and insects, especially in their nuclei. Thus, according to 

 Hodge, in the sparrow, in the morning, after resting, the cells of 

 the brai-hial ganglia, which innervate the wing-muscles, have clear, 



lud, 



■^icular nuclei (Fig. 241, A), while 



in the evening. 



after 



