ON THE STUDY OF PLANT ENZYMES. 109 
as this method is of value in discriminating between glucose and 
fructose (compare Muster and Woker, Pfliigers Archiv, 1913, 155, 92). 
On adding a féw drops of methylene blue to a freshly prepared solution 
containing one per cent. of the carbohydrate, together’ with half of one 
per cent. of solution of sodium hydroxide, the blue color is almost 
immediately discharged in presence of fructose, but only after a certain 
interval—15 minutes—by glucose. After standing, the glucose solu- 
tion acts much more rapidly, whereas the fructose is less active than 
at first. Most probably the active agent is the enolic form common 
to both sugars; as Lobry de Bruyn was the first to show, this is 
formed from both by the action of alkali. |The possibility of the 
formation of fructose from glucose and vice versa in this manner in 
the plant must not be overlooked. The methylene blue test has been 
applied to a number of carbohydrates, so as to compare their rela- 
tive rates of enolisation. Indigo-blue solution, which changes from 
green to red, and finally to yellow, as it is reduced, is an equally 
sensitive agent. In all cases, agitation with air restores the colour; 
the colour is not destroyed in faintly acid solution. 
The behaviour of lipase has been further studied during the year. 
It has been shown that synthesis takes place under the influence of 
the enzyme to the greatest extent in the absence of all but traces 
of water, and that the presence of even ‘a small proportion of water 
greatly favours action in the reverse direction.! 
In view of the presence of ammonia in the nodular growths appear- 
ing on the roots of Leguminose, it appeared probable that 
the enzyme urease would be found in these. It has been detected 
in the nodules from Lupins and a number of other Leguminosae. 
Attempts to detect the enzyme in organisms cultivated from the 
nodules have thus far been attended with negative results. 
Mr. Benjamin, working at the Hawkesbury Agricultural College, 
near Sydney, Australia, has detected urease in nodules from several 
Australian plants, including wattles; also on tubercles derived from 
the Cycad Macrozamia spiralis. He has found urease also in the seeds 
of Abrus precatorius. 
Correlation of Crystalline Form with Molecular Structure.— 
Report of the Committee, consisting of Professor W. J. PoPr 
(Chairman), Professor H. E. ARMsTRONG (Secretary), Mr. 
W. BarLow and Professor W. P. WYNNE. 
Tue following communications have been made to the Royal Society 
during the year :— 
Morphological Studies of Benzene Derivatives. WV. The Correlation 
of Crystalline Form with Molecular Structure: A Verification of 
the Barlow-Pope Conception of Valency-Volume. By Henry EF. 
' Proc. Roy. Soc. 1914, Series B, ‘Studies on Enzyme Action,’ xxii., Lipase (iv.) 
‘The Correlation of Hydrolytic and Synthetic Activity,’ by Henry E. Armstrong and 
H. W. Gosney. 
