invertase and had given the factor 0.317; it was found that its rota- 

 tion changed immediately to a greater negative value which corre- 

 sponded to a factor 0.324, thus verifying the above conclusion in a 

 different way. The inversions by invertase which gave the factor 

 0.317 were made in a solution which had been acidified with acetic 

 acid, as invertase acts only in an acid solution; the two acid strengths 

 of 0.01 and 1.0 normal were used and the factor was found to be the 

 same for both, 0.317. 



Other experiments have been made in which the solution was weakly 

 acidified with other acids to produce an acid medium in which the 

 invertase would act and for the inversion by invertase in these weak 

 acid solutions (five ten-thousandths normal) the following values of 

 the factor I/S&t 20 C. were found: Nitric, 0.315; sulphuric, 0.315; 

 oxalic, 0.314; citric, 0.314; tartaric, 0.320; phosphoric, 0.315; arsenic, 

 0.315 ; hydrochloric, 0. 315 ; and hy driodic, 0. 315. The average of these 

 values is 0.315, which is quite close to that just given for acetic acid 

 and for the neutralized hydrochloric inversions, 0.317; a difference of 

 0.4 C. in the temperature at which the readings of the inverted solu- 

 tions were made would account for this variation. Chas. A. Browne a 

 has found the value 0.325 for the inversion by hydrochloric acid when 

 the acid solution is read, and the value 0.317 after neutralization, num- 

 bers which are practically identical with those given here. Weber 

 and McPiaerson 6 find at 20 C. the factor 0.317 for inversions by 

 hydrochloric acid, correction being made for the influence of the acid. 



L. M. Tolman c finds the factor 0.318 for acid inversions, the acid 

 being corrected for, and states that, "if an inverting agent could be 

 obtained which had no effect on the invert sugar, the question of con- 

 centration [influencing the factor] would practically be eliminated. 

 But the elimination of this error would necessitate the determination 

 of a new factor which would in all probability be 141.79 [i. e., 0.3179] 

 or perhaps a little less." Invertase fulfils this requirement and its 

 factor is 141.7. 



It is thus certain that the factor for the inversion of cane sugar by 

 invertase is considerably less than the factor for the usual hydrochloric 

 acid inversion, that its value at 20 C. approximates 0.317 closely, and 

 that the difference between the factors for invertase and hydrochloric 

 acid is due to the effect of the acid on the rotatory power of invert 

 sugar. 



These experiments also prove that the hydrolysis of cane sugar by 

 invertase is a complete one, for just as much invert sugar was formed 

 by the invertase inversion as by that due to the strong hydrochloric 



U. S. Dept. Agr., Bureau of Chemistry, Bui. 110, p. 44. 

 b J. Amer. Chem. Soc., 1895, 77: 324. 

 c J. Amer. Chem. Soc., 1902, 24: 523. 

 Cir. 50. 



