Compressed Air; 2 Poisoning 717 



the reflex acts of the spinal cord,- after being considerably excited, 

 are checked. 



The fact that the convulsions come from the spinal cord, com- 

 municating its excitation to the muscles by means of the motor 

 nerves, is abundantly proved by experiments in which the motor 

 nerve has been cut: Example: 



Experiment CCLXXIV. June 20. Frog; left sciatic nerve cut. 



3 o'clock in the afternoon; subjected to 3 superoxygenated atmos- 

 pheres, containing 60.5 per cent of oxygen, 3 x 60.5 = 181.5 = 9 atmos- 

 pheres of air. 



Respiration ceases for a moment. 



June 21. Respirations very rare; eyes protruding with widely 

 rounded pupils; frog is swollen, rather weak; no convulsions. 



June 22. 11 o'clock in the morning. No respiration; weak; eyes 

 closed by the transparent lid. Clonic convulsions beginning in the 

 right front leg, then becoming generalized, except in the left hind 

 foot; then general stiffness; then weakness. 



These attacks are excitable at will, by shock; but the frog soon 

 seems insensible, as if dead. 



Sudden decompression; no effect. In the outer air, does not 

 breathe; the heart, exposed, beats 50 times per minute; the blood, 

 which was red at first, grows progressively darker. 



After about a quarter hour, excitation brings on new convulsive 

 attacks, like the preceding. On exciting the right hind foot, move- 

 ments of the right front leg are produced, but not of the left. 



Frequently fibrillary contractions, in the muscles of the chest 

 especially and also in the limbs, except the left hind foot. 

 During the convulsions, the heart does not seem altered. 

 Dies about 2 o'clock. 



So section of a motor nerve prevented all convulsive move- 

 ment, fibrillary or generalized, from appearing in the correspond- 

 ing muscles. 



Since oxygen injures the spinal cord, like strychnine, phenol, 

 etc., convulsions should be prevented by chloroform, which, as I 

 have shown before, 2 acts particularly on the spinal cord. In fact, 

 this very thing happened in the following experiment. 



Experiment CCLXXV. February 26. Etherized sparrow, put into 

 the receiver; rouses during the compression. I put some drops of ether 

 into the vessel in which the oxygen sucked in by the pump is bub- 

 bling in the potash, and raise the pressure to 5 atmospheres, 4 of 

 which are oxygen. 



The bird becomes unconscious again, after some quiverings of the 

 feet; he dies slowly, in 25 minutes, without any convulsion. 



Huge cranial suffusions. 



The lethal air contains CO, 2; O? 76. The original pressure of the 

 oxygen was therefore about 78x5 = 390, corresponding to 19 atmos- 

 pheres of air. 



