On Relationship between Staircase phenomenon and fatigue. 299 



muscular tissue.^) Two frogs were taken, A and B, B was 

 injected with 4 ccm of a 5 "/^ Solution of Esserin Sulphate, after 

 about 15 minutes the respirations of B were very slow and 

 subject to periodical pauses of long duration. Each Frog was 

 then stimulated in the anal region with the interrupted current 

 obtained from one Edison-Leland cell, the coil being pushed 

 home, for half an hour. The respiratory movements of B 

 ceased almost entirely but the limbs in both frogs went into 

 tetanic contractions. After Stimulation had been eompleted 

 the brains of both frogs were extracted, divided longitudinally, 

 and stained for 4 minutes in 2°/^ Neutral Red. After then 

 soaking them in Ethyl Acetate for from 40 to 50 minutes, a 

 most marked diflference between the two brains was observed; 

 A was red to pink while B was yellow to pink. Evidently 

 far more acid had been developed in the brain of the frog 

 which had not been previously treated with Esserin than in 

 the brain of the frog which had, although in both cases the 

 musculature was thrown into violent tetanic contractions, owing 

 to the direct Stimulation of the muscles and motor fibres. 

 II. On the influence of Various Substances. applied directly to 

 the Medulla Oblongata, upon the Respiratory Rhythm in Frogs. 

 Recent experiments by Maxwell^) have shown that the 

 nerve-cells in the cerebral cortex are not stimulated by the 

 ordinary nerve-stimulants, such as Oxalates, citrates, tartrates etc. 

 Garrey') has shown that inhibition of the heart-beat may 

 result from appljdng isotonic Solutions of these salts directly 

 to the spinal cord or medulla; it is probable, however, that 

 in these experiments it is the nerve-fibres or nerve-endings 

 which are stimulated and not the nerve-cells; in Maxwell's 

 experiments the possibility of stimulating nerve-fibres was ex« 

 cluded, and no motor effect could be detected as a result of 

 applying these salts to the cortical nerve-cells. These results 

 would not justify us in concluding, however, that no chemical 

 substances can modify the processes which occur in nerve-cells. 



1) HarnaokundWitkowski, Arch. f.experim.PathoI.u.Pharmakol. 

 5, 401, 1876. — Harnack undMayer, Ibid. 12, 366, 1880. — Cf. Cushny, 

 ,,Pharinacology and Therapeutics", third Edn., New York, p. 324. 



2) S. S. Maxwell, Joum. of Biolog. Chem. 2, 183, 1906. 



3) Garrey, California State Joum. of Medicine, July 1907. 



