1918] CURRENT LITERATURE 279 
paralleling the temperature curve, the ratio for the second series has a maximum 
of 1.60 at 4 P.M. and exceeds unity at all hours except at 2 A.M., when it drops 
to 0.94, but still roughly parallels the temperature curve. In the final series 
the ratio ranges between 1.93 at 7 A.M. and 1.14 at 3 P.M. as extremes. 
For total sugars (hexoses plus saccharoses) the maximum in the August 26 
series is 5.26 per cent, reached at 12 noon; the minimum, 1.70 per cent, is 
attained at 4 A.M.. On September rr the maximum of 16.08 per cent is 
attained at 4 a.M., the minimum of 9.98 per cent at 8 A.M., with a second rise to 
15.29 per cent at6P.mM. On October 11 the maximum of 20. 99 per cent occurs 
at 7 P.M., is followed by a slightly lower maximum at 3 A.M., with the minimum, . 
14.5 per cent, occurring at 7 A.M. 
In the first series, pentoses vary during the daylight hours only between 
0.37 and 0.45 per cent, dropping again to 0.36 at 8 p.M., only to rise slowly 
through the night to 0.52 at 4 A.M. Pentosans remain practically constant 
through the day in the neighborhood of 5.5 per cent, with a maximum of 5.96 
at 4 P.M. In the second series, the fluctuations in pentose have much wider 
limits; there is increase from 0. 34 to 0.68 per cent between ro A.M. and 2 P.M., 
followed by a fall to o. 45 at sunset and a subsequent rapid rise to 0. 71, remain- 
ing stationary through the dark hours and dropping suddenly to 0.5 at 4 A.M. 
Pentosans rise slightly between noon and 2 P.m., then remain stationary until 
4 A.M., when there is a second slight rise, but the fluctuations are between 4.42 
and 5.9 per cent as extremes. In the final series, pentoses remain almost 
unchanged at 0.9 per cent from 9 A.M. until 9 P.M., declining to a minimum of 
©.61 per cent at sunrise (7 A.M.). Pentosans here show very slight fluctuations, 
(6.21 to 6.55 per cent). The total percentage of material soluble in alcohol 
falls slowly throughout the day in the first series, attaining a minimum at 
4 P.M., then remains nearly constant through the night. In the second series 
there is a decline in alcohol-soluble constituents from 4 A.M. to 1 P.M., then a 
rise continuing until sunset, with a drop between 6 and 8 P.M., then a very slow 
rise from 47.2 to 51.3 per cent between 8 p.m. and 4 A.M. In the third series 
the percentages of alcohol-soluble materials are almost constant from 7 A.M. 
to 9 P.M., varying only from 52.0 to 54.9 per cent, then run down at 11 P.M. to 
47.9 per cent, only to return at the next sampling to the general level. 
The increases in pentosans throughout the day in the first and second 
series are attributed in part to the building of new ligneous tissue, in part to the 
formation of gums which play the réle of reserves. In the third series, when 
the leaves have ceased to grow, the fluctuations are apparent rather than real, 
being due to fluctuations in total sugars. The striking feature of the curves 
for sugar are the two night maxima which occur in both second and third series, 
since both hexoses and saccharose increase synchronously to a point higher 
than that reached during insolation, their sum total also exceeding that attained 
in the day and reaching its greatest amount at the same time, between midnight 
and 3 A.M, in both series, so that the results cannot be due to interconversion. 
