SUBCUTANEOUS INJECTIONS OF RINGER'S FLUID 323 



able effect upon the working power of the muscle is to be attributed 

 to the ethyl alcohol, or to the increase of the circulating medium. 



In order to test this, we made parallel, simultaneous experiments, 

 injecting into one frog the solution of alcohol, and into another an 

 equivalent amount of water, or Ringer's fluid. The operative pro- 

 cedure and experimental method were essentially those of Lee and 

 Salant : After removal of the cerebrum, with due precautions against 

 loss of blood, one leg of each animal was ligatured and the fluid 

 injected into the dorsal lymph sac. Simultaneous tracings were then 

 taken from the excised muscles of the ligatured legs ; and later (usually 

 about 45 minutes), simultaneous tracings were taken from the other 

 legs. Edison-Lalande cells were used to insure constancy in the 

 strength of the stimulating current, the primary circuit being 

 interrupted, and the " making " induction shock short circuited by a 

 mechanical "Ablender." The rate of stimulation was usually about 

 once every two seconds. In some experiments the contractions were 

 isotonic, the same weight being lifted by the two muscles of the same 

 frog. In other experiments the auxotonic method was employed, 

 the muscle contracting against the resistance of an open, spiral, brass 

 spring, accurately adjusted so as to insure equal initial tension and 

 the same direction of pull. 



The work done during the same time by two muscles, in fatigue 

 tracings taken on drums revolving at the same, uniform speed, and 

 with the same rate of stimulation, is proportional to the areas included 

 between the base line,* the first and last tracings of the given period, 

 and the line joining the highest points of the contraction records. 

 These areas, were therefore measured with a planimeter, and the 

 work done by the two muscles readily compared. 



RESULTS. 



Thirteen successful experiments were thus made upon the effects 

 of injecting the 10 per cent alcohol, and 13 simultaneous, parallel 

 experiments upon the effects of injecting water, or Ringer's fluid. 

 The results with each of these fluids are given separately, for con- 

 venience, and the percentage of increase of work done in the same 

 time (until the appearance of marked fatigue) is represented by giving 

 the number of experiments in which a given range of increase occurred. 



*In our experiments the contractions returned to the base line. 



