EUPHORBIA VIRUS A AND ALOE DIGHOTOMA 
59 
the atmosphere. The infliction of a wound therefore lowers the internal 
pressure. Since the ramifications of the latex-system extend into the tissue- 
dianh^flo-ms nf tliM rd+.b pressure of the gases confined by these diaphragms 
the withdrawal of latex. If the pith region con- 
f gas, this expansion would be equal and practically 
le plant. Since, however, any change in pressure 
nitted through diaphragms of unequal thickness 
ticity, and since the amounts of latex withdrawn 
ill certainly be unequal, its rate of transmission 
onse in different reservoirs will not be the same, 
whether the gas-expansion caused by such an 
fc. ned in the various experiments would be sufficient 
| aperature observed in the unwounded branches. 
t, my colleague Dr J. C. Beattie has kindly made 
• a column of dry air. 
itic change of volume let v be the volume, T the 
§ ratio of the two specific heats, then the relation 
{^J 
2V _1 = constant. 
1. vhich an initial volume v at temperature 40 C. 
I I cally, in order that the temperature may fall 4° C., 
} | O hen 
5 m § (xV)y~ l _ 313 
o 'p S. vv- 1 309 * 
X ^ O* 
~ value for air) we find x 1032, the volume must 
■ _ V ately 32 °/ Q ; in order to produce a fall of 1 viz. 
5 rease must be slightly over 1 /. 
£ ■ pressure p and temperature 1 for an adiabatic 
r fy 
= constant, 
II of 4° C. from an original temperature of 40° C. 
(xp)y- 1 _ 309 y 
py~ l " 313 ^’ 
rj = 0'956 for 7 = 1‘4, 
dll be approximately 4'4 °/ o ; for a fall of a degiee 
tse in pressure will be approximately 1 1 /• 
U of temperature of 4 C. 1 of such a gas at 40 C. 
.1 in an unwounded stem was 4°'5C. (see Table I). 
5—2 
