THE PHENOMENON OF CONTRACTION. 47 



obtained, some of which will be referred to specifically.* It should 

 be borne in mind, however, that the ergograph in this form does 

 not enable us to compute the total work that the muscle is capable 

 of performing. It is obvious that when the point of complete 

 fatigue is reached, as illustrated in the record, Fig. 23, the muscle is 

 still capable of doing work, that is external work, if we replace the 

 heavy load by a lighter one. For this reason some investigators 

 have substituted a spring in place of the load,f giving thus a 

 spring ergograph instead of a weight ergograph. Although with the 

 spring ergograph every muscular contraction is recorded and the 

 entire work done may be calculated, it also possesses certain theo- 

 retical and practical disadvantages, for a discussion of which refer- 

 ence must be made to the authors quoted. 



The weight ergograph has, so far at least, given us the most sug- 

 gestive results. Among these the following may be mentioned: 

 (1) If a sufficient interval is allowed between contractions no fatigue 

 is apparent. With a load of 6 kilograms, for instance, the flexor 

 sublimis showed no fatigue when a rest of 10 seconds was given 

 between contractions. (2) After complete fatigue with a given 

 load a very long interval (two hours) is necessary for the muscle to 

 make a complete recovery and give a second record as extensive as 

 the first. (3) After complete fatigue efforts to still further contract 

 the muscle greatly prolong this period of complete recovery, a 

 fact that demonstrates the injurious effect of straining a fatigued 

 muscle. (4) The power of a muscle to do work is diminished by 

 conditions that depress the general nutritive state of the body 

 or the local nutrition of the muscle used; for instance, by loss of 

 sleep, hunger, mental activity, anemia of the muscle, etc. (5) 

 On the contrary, improved circulation fh the muscle produced 

 by massage, for example increases the power to do work. Food 

 also has the same effect, and some particularly interesting experi- 

 ments show that sugar, as a soluble and easily absorbed foodstuff, 

 quickly increases the amount of muscular work that can be per- 

 formed. (6) Marked activity in one set of muscles the use of 

 the leg muscles in long walks, for example will diminish the 

 amount of work obtainable from other muscles, such as those of 

 the arm. It is very evident that the instrument may be used to 

 advantage in the investigation of many problems connected with 

 gymnastics, dietetics, stimulants, { medicines, etc. 



A point of general physiological interest that has been brought out in 

 connection with the use of the ergograph calls for a few words of special 

 mention. Mosso found that if a muscle e. g., the flexor sublimis is stimu- 



*Mosso, "Archives italiennes de biologic," 13, 187, 1890; also "Archiv f. 

 Physiologic," 1899, p. 191, 342. Lombard, a Journal of Physiology," 13, 1, 1892. 



t Franz, " American Journal of Physiology," 4, 348, 1900; also Hough, 

 ibid., 5, 240, 1901. 



JSchumberg, "Archiv f. Physiol.," 1899, suppl. volume, p. 289. 



