92 
Notes. 
same time new lateral buds might be shooting out. These considera- 
tions led Schimper to conclude that calcium plays no fundamental part 
in the conduction of carbohydrates. 
This conclusion still left unexplained the abnormal accumulation of 
starch in plants cultivated in solutions devoid of calcium. It appeared 
to me that the explanation might be very simple, namely, that though 
potassic oxalate did not prevent the transport of sugar, it was 
capable of arresting the change of starch into sugar. It naturally 
suggested itself that acid potassic oxalate should either prevent diastase 
from being formed or should stop its action. I therefore made some 
experiments on the influence of acid potassic oxalate on diastatic 
action. 
In these experiments a strong solution of ‘ extract of malt ’ was used 
in place of pure diastase, to act upon a clear portion of a -5 per cent, 
solution of arrowroot-starch. Bacteria were kept at bay by means of 
traces of thymol. In each case 10 cc. of starch-solution were mixed 
with 10 cc. of certain strengths of acid potassic oxalate solution ; then 
10 cc. of the solution of ‘ extract of malt ’ were added. The following 
table shows the result of experiments conducted at a temperature of 
about 30° C, and commenced at 1 1 a.m. 
Solutions. 
Resulting percentage 
of acid potassic oxalate 
in the whole mixture. 
Colour v 
12 a.m. 
/hen treated with i 
1.30 p.m. 
odine at 
4.30 p.m. 
A. B. C. D. 
.6, .5, .3, .26 
Blue- 
Blue 
Blue 
E. 
•13 
Dirty brown 
Lighter brown 
Yellow 
F. G. H. K. 
•04, *02, .OI3, O 
Yellow 
Yellow 
Yellow 
This preliminary set of experiments roughly showed that the action 
of diastase is retarded by even dilute solutions of acid potassic oxalate. 
I subsequently found that similar rough observations had been made 
by Detmer, whose investigations are quoted in Schleichert’s Das 
diastatische Ferment der Pflanzen. Quantitative observations, in 
which pure diastase was employed, have been conducted by Mr. J. H. 
Manley, of the Magdalen College Chemical Laboratory, Oxford ; these, 
though not yet complete, confirm the rough observations. 
It became essential to see next if this soluble oxalate had the same 
action on starch in the living leaf. For experiments I selected sub- 
