30 BOTANICAL GAZETTE [JANUARY 
of water. In the case of leaves which bore spots, he observed 
that they still remained after drying, and concluded that they 
were not caused by the heating of the stem. By heating only 
the outer portions of a ‘‘tolerably thick” Fagus stem with steam 
for “‘a short time,” he found that the leaves remained turgid for 
9 days, and assumes that the plant can conduct water if only some 
of the living cells are present. In the case of several other experi- 
ments on woody stems, portions of which have been killed with 
meters above the killed portion. The wilting supervened in these 
cases no sooner than in other cases in which no stoppage was — 
observed. He believes that wilting may occur in cases when — 
stoppage is not present. 
URSPRUNG (34-37), parallel with steam, has also employed 
girdling experiments on about 20 species of plants besides Fagus. 
When 10 cm. of richly leaved branches of Ulmus and Populus 
longer turgescent, some ten times as long, when 3 cm. than when 
80 cm. are killed. His girdling experiments gave very divergent — 
results in the different plants studied. Viburnum kept its leaves — 
turgescent for 45 days; Ulmus leaves began to wilt in 1 day. 
Ursprunc concludes from these heating and girdling experiments — 
that two factors are concerned in the death of the leaves: (1) 
increased resistance to sap-flow, (2) diminution of the power of 
transportation. He believes that the very great difference in 
hold water under the condition of the experiment. A slow water 
transport may be due to an increased resistance to flow or to 4 
decrease in the power of the transportation of the stem. Since 
stoppage of the vessels is not universally present in treated 
stems, he thinks that the increased resistance to flow is not to be 
considered. According to him the transport of water is partly 
