Notes on Recent Literature. 
3 6 
It is generally stated that all chemical change must necessarily 
he in abeyance at such temperatures, and that therefore the seed 
cannot be in any other than a state of static equilibrium. A few 
chemical changes, however, still take place at these low tem¬ 
peratures, such as the union of hydrogen and fluorine, so that it is 
not philosophical to say that absolutely no change can take place in 
the cell. We need only recall the modern conception of the nature 
of the general relations between temperature and chemical change. 
According to this the rate of change will be lowered by some 
constant fraction for every 10°C fall of temperature. Therefore, 
however low the temperature, the change will only be indefinitely 
retarded, not absolutely stopped. It may well be that there will 
not be enough C0 2 produced to be detectable in a ten years, but 
who shall say that change has ceased. Our methods of analysis, 
which demand a large aggregate of molecules for any demonstra¬ 
tion, are incapable of settling this philosophical question. We can 
only set up an arbitrary quantitative standard of a minimum, and 
agree to ignore all amounts below this. 
Similar must be the relation between dryness of the seed and 
the rate of respiratory or other cherpical change in the cell. There 
is no doubt that the rate of change falls off rapidly as dessication 
proceeds. Kolkwitz has shown that at summer temperatures one 
kilogram of Barley produced per 24 hours 3-59 mg. of C0 2 when it 
contained 19-2% of water, P4 mg. when it contained 14% of water, 
and OSS mg. when it contained 11% of water. This curve might be 
extended, when it will continually approach the value of zero, but at 
no degree of dessication will the change theoretically cease. 
It is not even as if we could absolutely dry our seed ; we can 
only go on till it is in equilibrium with the particular drying agent 
used: there is no finality in such procedure. 
Philosophically then we reach the conclusion that neither cold 
nor dessication is capable of distinguishing experimentally between 
the two hypotheses as to the nature of the latent vitality of seeds. 
Experimental tests based upon the power of resisting extreme high 
temperatures are not open to this critical objection, but this leads 
us beyond the scope of the present review. 
F.F.B. 
R, Mauley, Printer, 151, Whitfield Street, London, W, 
