570 Experiments 



evidently interferes here, and this dangerous factor is nothing but 

 oxygen. 



D. Compression with air of low oxygen content. 



Let us now examine this hypothesis of a fatal action of the 

 compressed oxygen with the effect of killing the bird before it has 

 formed the percentage of carbonic acid required by the formula 

 C0 2 x P = 26. Let us refer to Table VII. If the explanation I have 

 just given of the lowness of the numbers of Column 8 (C0 2 x P) 

 measuring the tension of the carbonic acid is correct, that is, if this 

 lowness is due to the high value of the numbers of Column 5 

 (0 2 x P) , measuring the oxygen tension, the first will increase if 

 I lower the second by lessening the factor O. without changing 

 factor P. 



It was enough then to repeat the experiments, injecting into the 

 compression apparatus not ordinary air, but air of low oxygen 

 content. This was done in the following experiments. 



Experiment CXXXIV. April 20. 



Greenfinch (Loxia chloris, Lin.) Put into the apparatus for 5 

 minutes, then raised to 6 atmospheres of air; cock closed at 2:50. At 

 3 o'clock, we began to inject air very low in oxygen, and at 3:11, 

 reached 22 atmospheres. 



The moment of death cannot be clearly determined, but the bird 

 had no convulsive movements at any time. 



Considerable cranial suffusions. 



Lethal air: CO^ 1.1; O* 9. 



Initial oxygen tension: 226. 

 * Final CO tension: 24.2. 



Experiment CXXXV. June 27. 



A sparrow is placed in the apparatus, and air in which phosphorus 

 has burned and which has become very low in oxygen is pumped in; 

 the pressure is taken to 5 atmospheres. 



The cock is closed at 3:55; the bird dies at 5:50. It lived therefore 

 1 hour 55 minutes; bloody suffusions, not very extensive; some gas 

 bubbles in the right heart. 



Composition of lethal air: CO 4.5; O 5.. 



Initial oxygen tension: 50. 



Final CO- tension: 22.5. 



Experiment CXXXVI. June 29. 



Sparrow at 12 atmospheres, 1 of air and 11 of air in which phos- 

 phorus has burned. 



Entered at 2:45; dead at 3:15; lived 30 minutes; cranial suffu- 

 sions; gas in the right heart. 



Lethal air: CO* 2.1; O 4.8. 



Initial oxygen tension: 84. 



Final CO tension: 25.2. 



