404 FATIGUE, EXHAUSTION AND REVIVAL. [BOOK I. 



of the rest of the muscles from the nervous centres was followed by a 

 diminution 



of consumed 37*1 p.c. 



of C0 2 produced 29 -92 p.c. 



but here the heart was weak and the circulation disturbed l . 



Whatever may be the nature of the influence exerted by the 

 nervous system, it is probably reflex in its origin, and excited by the 

 difference of temperature between the skin and the external medium. 

 Liebermeister and Gildermeister 2 shewed in the case of men that the 

 production of heat and the formation of carbon dioxide increase on 

 the application of cold to the surface of the body ; and Rohrig and 

 Zuntz confirmed this in the case of rabbits, by immersing them in 

 cold baths. If, however, the animals be first curarized, immersion in a 

 cold bath no longer stimulates the interchange of oxygen and carbon 

 dioxide, but rather tends to diminish the amount of both 3 . In other 

 words, the reflex mechanism is in abeyance, and the bath, by directly 

 cooling the tissues, renders their various processes more sluggish. 



Curare-poisoning seems to have no diminishing influence over the 

 nitrogenous excretions of the urine 4 . 



With regard to the constitution of muscle itself after separation from its 

 cerebro-spinal centres, it is said that it contains less creatine 5 but more 

 glycogen". 



SECT. 4. FATIGUE, EXHAUSTION AND REVIVAL. 



Signs of Muscles are incapable of contracting continuously 



Fatigue. for an indefinite time. They become fatigued more 



or less quickly, and are finally exhausted, when the most powerful 

 stimulus fails to cause a contraction. The evidence of fatigue is a 

 slow contraction of small amplitude. The muscle contracts slowly 

 to its maximum, which is abnormally small; but especially does 

 it elongate more slowly and less perfectly than usual, approximating 

 the condition of the 'idiomuscular contraction' (p. 843) 7 . The 

 rate of transmission of the wave of excitation is also probably 

 diminished during fatigue 8 . 



1 Pfliiger, pp. eft., p. 320. 



2 Quoted by Eohrig und Zuntz, pp. cit. Pfliiger's Arch. f. d. ges. PhysioL, Vol. iv., 

 1871. a Pfliiger, Op. eft., p. 303. 



4 Voit, Zeitsch. fiir Biol., xiv. p. 57, 1878. See Hofmann and Schwalbe's Jahres- 

 berichte, Vol. vn. pt. iii. p. 272. 



6 Sczelkow, Centralblt. /. d. med. Wiss., 1866, p. 481 (Original not seen). 



6 Macdonnel, "On the formation of Sugar and Amyloid substance in the Animal 

 Economy," Proceed. Roy. Irish Acad., Vol. vn. p. 276, 1860. Also Observations on the 

 Functions of the Liver, Dublin, 1865, p. 23. Ogle, "A Hypothesis as to the ultimate 

 destination of Glycogen, " St George's Hospital Reports, in. p. 149, 1868. Chandelon, 

 " Ueber die Einwirkung der Arterienunterbindung u. der Nervendurchschrieidung auf den 

 Glycogengehalt der Muskeln." Pfliiger's A rch. /. d. ges. PhysioL, Vol. xin. p. 626, 1878. 



7 See also the condition known as "Contractur, or remnant of contraction," which 

 follows powerful direct stimuli: Tiegel, Pfliiger's Arch., Vol. xm. p. 71, 1876, and 

 Hermann, Pfliiger's Arch., Vol. xni. p. 370. 



8 See Hermann's Handbnch der Physiologic, Vol. i. Abth. i. p. 58. 



