ON THE HYDROLYSIS OF SUGARS. 287 



effect measured equally well. This, however, is contrary to the conclusion 

 of Reformatsky and also Levi (vide Section H). Long extended 

 |Qg^ Bechamp's observations on inversion by certain feebly stable salts, 



such as ferrous chloride and cadmium chloride. He calculated 

 the degree of hydrolysis of various salts at 85° 0. by Walker and Aston's 

 method, the influence of the salts themselves on the rate of inversion by the 

 free acid being, as he remarks, neglected. This work was further extended 

 leqq ^Y Kahlenburg, Davis and Fowler, who measured the hydrolysis 



of various salts by means of sugar, using the freezing-point method 

 in the case of coloured salts. The order of basicity of the metals as 

 determined in this way is much the same as their 'solution tensions,' 

 1899 aluminium, however, forming a notable exception. Ley, in the 



same year, published a reseai'ch on similar lines. Some salts, 

 according to Ley, such as LiCl, KCl, MgClg, have no invertive power 

 at all ; whilst others, such as AI2CI6, cause considerable inversion and 

 also have the power to hydrolyse methyl acetate. The values obtained 



for the hydrolytic decomposition of aluminium chloride in -- solution 



are 8'04 per cent, by the sugar-inversion method and 8"8 per cent, by 

 1903 *^® methyl acetate method. Walker and Wood made a careful 



comparison of the two methods and found that if a correction 

 were applied for the accelerating efiiect of the salt in the case of cane 

 1 QQi sugar, the two methods of estimating gave results in very close 



agreement. This subject has already been reported on by Farmer 

 to the British Association in 1901. 

 , QQj, Kullgren observed that inversion at 100° by salts such as MnCLi 



or CdClo does not follow a mass-action curve because an acid is 

 progressively formed from the sugar itself. With AljClg a better con- 

 stant is obtained, because the disturbing effect is by comparison smaller. 



M. — Hydrolysis of Stigars other than Cane Sugar. 



Compared with the facility with which cane sugar is hydrolysed, all 

 the other biose sugars and the glucosides are much more difficult of attack. 

 1882 ^^^^ ^'^^ noted by Meissel, who found that maltose is intermediate 



in stability toward acids between cane sugar and lactose. 

 1885 Urech discovered the same fact and explained the different 



stability of the three sugars by the 'gradation from fructose to 

 galactose through glucose.' 



,ggg Bourquelot, who was in ignorance of the two foregoing re- 



searches, also showed that maltose is enormously more stable than 

 cane sugar towards acids. A saturated solution of carbon dioxide at 38° can 

 invert cane sugar but apparently is without action on maltose. Sigmund 

 1898 ™6*sured the rate of hydrolysis of maltose between 63°-7 and 83°-8. 

 The action follows Wilhelmy's Law and when the temperature is 

 varied the velocity varies according to Van't Hoff's equation. The initial 

 volume-normal concentration of the maltose has considerable influence, as 

 in the case of saccharose {vide Section G 2). 



1904 Armstrong and Caldwell studied the rate of hydi'olysis of 



lactose and maltose at 60°, 74° and 99 C°. The hydrolysis follows 



Wilhelmy's Law and is in every way similar to that of cane sugar, except 



that it proceeds much slower. The effect of concentrations of sugar and 



