316 Prof. H. I. Armstrong and Dr. W. H. Glover. [Apr. 2, 
The values deduced for cane-sugar are in fair agreement with those 
obtained by other workers in our laboratory. Contrasting the mean values, 
they are as follows :— 
Nitric acid. Chlorhydric acid. Sulphuric acid. 
Cane=sucvar = sees 464 500 549 
Rathimose. 2 .cceece: 390 419 446 
The three acids differ in their activity towards both sugars: the cause of 
this difference will be discussed in a separate communication, dealing with 
the sucroclastic action of acids generally. 
It is clear that raftinose is less easily hydrolysed than cane-sugar, at a rate 
nearly one-fifth less than that at which the latter undergoes change. The 
ratios for each acid are nearly the same in the case of nitric acid and 
chlorhydric acid, but sulphuric acid is relatively less active towards raffinose 
—a result not without interest, the significance of which, however, need not 
be discussed here. 
Hydrolysis of Cane-sugar and Raffinose by Inwertase. 
In contrasting their behaviour towards invertase, comparative experiments 
were carried out simultaneously with the two sugars under similar 
conditions. A known volume of a very weak solution of invertase at 25° C. 
was added to a known volume of the sugar solution of definite concentration, 
also at 25°, contained in a Jena-glass flask; after adding a few drops of 
toluene, the flask was corked up and placed in an incubator kept at 25°. At 
stated intervals, 20 c.c. samples were withdrawn from the flask by means of a 
pipette and run into small Jena-glass flasks, each containing a single drop of 
a strong aqueous solution of sodium hydroxide. By this means the action of 
the enzyme was at once arrested and equilibrium established between the 
stereo-isomeric forms of the sugars in solution. The final values were 
obtained by keeping part of the solution at 25° C. during 24 hours, at the 
end of which time a drop of sodium hydroxide solution was added as before. 
In order to obtain the initial values, a drop of sodium hydroxide solution was 
added to a known volume of the enzyme solution, which was then mixed 
with the sugar solution in the same proportion as in the experiment. 
In the preliminary experiment the raffinose used was that supplied by 
Kahlbaum. The rotatory powers of the solutions were determined in sodium 
light. 
The results obtained are exhibited in Table II, the values given under K 
a 
being those deduced with the aid of the formula K = 2 logio 
=e apt 
