Solubility of Air in Fats, and its Relation to Caisson Disease. 367 



represent the volumes of gas, reduced to 0° and 760 mm., contained in 100 c.c. 

 of the oil at the temperature recorded, when saturated with air at a pressure 

 of 760 mm. To calculate these values, it was assumed that the specific 

 gravity of olive oil at 15° is 0*917, and at 37°, 0*902.* The specific gravity 

 of cod liver oil, compared with that of water at 15°, was found by direct 

 experiment to be 0*928 at 15°, and 0*914 at 37°. 



100 c.c. of olive oil contain- 



At 15° C. 



Mean. 



At 37° C. 



Mean. 



Oxygen . 

 Nitrogen 

 C0 2 .... 



c.c. 

 2-20 

 5-23 

 0-19 



c.c. 

 2-23 

 5-30 

 0-24 



c.c. 

 2-42 

 5'27 

 0-16 



c.c. 

 2-28 

 5-26 

 0-20 



c.c. 

 2-33 

 5-19 

 0-17 



c.c. 

 2-36 

 5 23 

 0-13 



c.c. 

 2-30 

 5*15 

 0-18 



c.c. 

 2-33 

 5-19 

 0-16 



100 c.c. of cod liver oil contain- 





At 15° C. 





Mean. 





At 37° C. 





c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



c.c. 



2-34 



2-31 



2 22 



2-29 



2-21 



2 22 



2-22 



4-95 



5-15 



5-07 



5-06 



5'05 



5'10 



5-08 



0-19 



0-25 



0-19 



0-21 



0-18 



0-24 



0-20 



Mean. 



Oxygen . 

 Nitrogen 

 CO, .... 



c.c. 

 2 22 

 5-08 

 0-21 



Considering only the mean values, we see that in the case of each oil the 

 solubility at 37° is within the limits of experimental error the same as its 

 solubility at 15° C. A similar constancy was found by Bunsen for the 

 solubility of oxygen in alcohol at temperatures from 0° to 24°, though 

 Timofjewf has since found that the solubility does slightly diminish with the 

 temperature. In any case the diminution is small (6*8 per cent, diminution 

 for oxygen and 5*2 per cent, diminution for nitrogen between 0° and 24°) and 

 if it exists at all in the case of these oils, it must be smaller still. A simple 

 proof of the slight effect of temperature on solubility is obtained by saturating 

 the oil at room temperature, and heating it gradually in a water bath. Not a 

 trace of gas is observed to come off if the temperature be kept at 97°, but at 

 100° it bubbles off in very small quantities. 



The observations on lard were carried out at one temperature only. Lard 

 melts at 36° to 48°, and solidifies at 27° to 30°, but if melted and shaken with 



* See Lewkowitsch, "Chemical Analysis of Oils, Fats and Waxes," London, 1898, 

 p. 454. 



t Timofjew, ' Zeit. Phys. Chem.,' vol. 6, p. 151. 



2 E 2 



