280 BOTANICAL GAZETTE [SEPTEMBER 
In the entire absence of both maltose and starch, the authors attribute this 
increase to the conversion into saccharose and invert sugar of some gummy 
substance, which is present in large amounts and which is precipitated in semi- 
crystalline form by basic lead acetate after treatment with taka-diastase. 
There is also an interconnection between the fall and rise of pentoses which 
occurs between 4 and 8 p.m., and the change in the opposite direction in sac- 
charose and hexoses. 
While pentosans make up 8.58 to 9.61 per cent of the insoluble matter of 
the leaves in the first series, there is an increase to 9.83-10.85 per cent in the 
second and a further increase to 13.70-15.35 in the third. While in the first 
series about one-half the saccharose and nearly all the hexoses are used up dur- 
ing the night, the second and third series show a very much larger amount of 
reducing sugars present at the beginning of the day, and the amount of these 
up to the attainment of the first maximum is always greater than that of 
saccharose, but when root growth is nearly complete, as in the third series, 
the range of variation in cane sugar in the leaf becomes much greater, the leaf 
apparently acting as a storage reservoir during insolation. The range of 
variations during growth is summarized as follows: 
’ Series and date Insoluble in alcohol Saccharose Hexoses 
1, August 26......... 57-5-62.9 1.50-3.11 0.20- 2.16 
ta Se piteia 10... <; 45-3 4.24-8.27 5.38- 8.90 
Ill, October 1m >... - 55.8 4.98-9.52 9.39-12.41 
Pentose Pentosans pagent ° ae ty eae . 
1, AU 965652..55. 0. 36-0. 52 5.19-5.96 O.13~). 72 4.70~ 5.32 
I, September i -.++| 0.34-0. 76 4.42-5.90 0.94-1.60 9.98-16.08 
IH, October rr... 0.61-0.92 6.21-7.15 1.14-1.93 14. 50-20.99 
Information as to the translocation of the sugars was obtained by making 
separate analyses of the midribs and petioles. At any given picking the 
amount of sugars and alcohol soluble matter is always greater in midribs than 
in leaves, greater in top halves of petioles than in midribs, and greater in lower 
halves than in top halves of petioles. In the first series, the total amount of 
hexoses and of apparent levulose in the stalks increases very rapidly during the 
forenoon to reach a maximum at noon, while the corresponding increases in 
dextrose and saccharose are extremely ny dextrose being actually larger in 
amount at midnight than at any time during the day. In the bottom halves 
of the petioles of the series, total hexose, apparent dextrose, ~ apparent 
levulose run very closely together, reaching a maximum at noon, declining 
steadily to midnight, and then separating, as levulose continues to acca while 
the others start upward again. Saccharose rises slightly from 6 A.M. to noon, 
and then remains stationary for the succeeding 18 hours. In the second series, 
