776 Experiments 



breathing or aquatic animals; I used sometimes compressed air, but 

 more often, for ease in arranging the experiments, air in which 

 the oxygen content had been increased. 

 Let us now discuss the experiments. 



Experiment CCCXXXVII. July 31. Placed in two large balloon 

 flasks, a certain number of fly pupae of the same age. 



A, the balloon flask is full of air. 



B, the balloon flask is full of oxygen. 



August 9. 6 emergences of flies in A, none in B. 

 August 10. All emerged in A, almost all in B. 



Experiment CCCXXXVIII. June 23. Silkworm cocoons, of the 

 same day (this experiment was made at the same time as Experiment 

 CCCXV). 



A, 12 were placed under an open bell. 



B, 12 in a flask of 3 liters, at a pressure of 2 atmospheres. 



C, 6 in a Seltzer water receiver with a capacity of 1 liter, at 5 

 atmospheres of air. 



The air in B and C was changed every other day. 

 July 8. A, all emerged. 



B, all the chrysalises were very active; 2 were transformed but 

 remained in their cocoons. 



C, the chrysalises were motionless; but when the skin was re- 

 moved from some of them, the butterfly was almost complete, with 

 some reflex movements. 



B and C were placed in the open air. 



July 15. B, one butterfly out of the cocoon and alive; a few others 

 transformed, but remaining in the cocoon and dead; under the skin 

 of the remaining chrysalises, the butterfly was found ready to emerge, 

 but dead. 



C, all the chrysalises were dead, without having made any move- 

 ments in the open air; under the skin of the chrysalis, the butterflies 

 were downy, but not far advanced. 



Experiment CCCXXXIX. April 15. Frog eggs already some- 

 what bilobed, placed in equal numbers in a similar quantity of water; 

 in addition, 5 tadpoles which had emerged 4 days before. 



A and A', under closed bells, ordinary air. 



B and B', under bells with 95% of oxygen, recently prepared by 

 chlorate of potash, well washed over potash and having remained 

 2 hours over pure water. 



These 4 bells were inverted over plates full of water and I 

 placed in the water outside, several tadpoles which were to serve 

 as controls. 



April 25. A and A', all emerged and very lively. 



B and B', all dead, after the eggs had developed almost to the 

 point of emerging. 



The controls are all in good shape. 



