840 Experiments 



excitable, the reflex acts are possible, and the heart is still beating. 

 But does this mean that the nervous anatomical elements alone are 

 attacked by oxygen? All that we have said hitherto is opposed to 

 that hypothesis; the considerable decrease of the intra-organic 

 oxidations, the death of lower animals, the death of plants and 

 ferments, all these phenomena show a universality of effect which 

 evidently must extend to the anatomical elements of the higher 

 animals. 



Yet I could not be satisfied in this case, any more than in any 

 other, with conclusions drawn from analogy. I thought direct 

 experiments necessary; but I confess that, seeing how well they 

 agreed with what appeared so probable, I did not make their 

 number very great. 



Experiment CCCCLXXVII. February 20. The hind-quarters of a 

 frog are cut in two, following the vertebral axis. 



A. One of these parts is left at normal pressure, hung in a closed 

 test glass, at the bottom of which water is placed to prevent desic- 

 cation. 



B. The other is hung similarly in the cylindrical glass apparatus, 

 in which the pressure is raised to 10 atmospheres of air with 80% of 

 oxygen. 



February 24. A. The sciatic nerve is no longer excitable; the 

 muscles still contract under the influence of a rather weak current; 

 they are neutral in reaction. 



B. Neither the muscles nor the nerves are excitable by the strong- 

 est currents. There is evident rigidity, and the muscles are very acid. 



Experiment CCCCLXXVIII. March 2, 2 o'clock. Halves of frogs 

 arranged as in the preceding experiment; A at normal pressure, B 

 at 15 superoxygenated atmospheres. 



March 3. 4 o'clock. A: sciatic nerve quite excitable; muscular 

 contraction very strong and very sudden, as in the normal state. 



B: The sciatic nerve can no longer be excited by any current. 

 The muscles still contract; but the contraction is slow, resembles a 

 kind of a cramp, and lasts after the stimulus has ceased. 



Experiment CCCCLXXIX. April 8. Experiment still arranged in 

 the same way; A at normal pressure, B at 3 atmospheres of air con- 

 taining 50% of oxygen, which corresponds in tension to 7.5 atmos- 

 pheres of air. 



April 10. A. Muscular contractions obtained with the inductor- 

 ium, the movable coil being 16 cm. from the exterior of the fixed coil. 



B. To get contractions, it is necessary to bring the coil to 5 centi- 

 meters. The contraction is accompanied by contracture. 



Experiment CCCCLXXX. June 12, 4 o'clock. The hearts of 4 frogs 

 are removed. These hearts are placed 2 by 2 in a capsule in which 

 they lie in the vitreous humor of a dog. 



A. Left at normal pressure. 



