72 



these animals was confined in seven cubic inches of 

 air, inverted over mercury, for the space of six days, 

 in a temperature varying from 7 to 8 Reaum. : 

 and the bulk of air was sensibly diminished. A 

 quantity of the residual air was then introduced into 

 an eudiometrical tube, filled with mercury, so as to 

 occupy one hundred parts : it was afterwards washed 

 in lime-water, and re-introduced into the eudiome- 

 ter, on which the mercury rose to 11. Phospho- 

 rus was next inflamed in the remaining air ; and 

 when every thing was again brought back to the 

 former temperature, the mercury had risen to 1 ly *. 

 This elevation of the mercury, he adds, is not very 

 sensible when phosphorus is employed, but when e- 

 qual quantities of the residual air, and of nitrous gas 

 were mixed together, so as to occupy two hundred 

 parts, the diminution was four, five, or six of these 

 parts, which indicated the quantity of oxygen gas 

 the air contained f. From these results, he is led to 

 conclude, in opposition to M. Vauquelin (55,), that 

 the consumption of oxygen gas., by the respiration 

 of snails, is not complete. 



58. With regard to this partial consumption of 

 oxygen gas by snails, it may be observed, that the 

 author found the same thing sometimes to happen 

 with slugs, which he, nevertheless, concludes gene- 

 rally to consume the whole of this portion of the at- 

 mosphere. The portion of oxygen gas unconsumed, 

 is likewise so very small, and the result, by the test 

 of phosphorus, so nearly approximates to that ob- 



* Memoirs or. Respiration, p. 146. ' Ibid. p. 



