35 
Longevity and Vitality of Seeds. 
was no loss of power of germination and we are reduced to thinking 
that if there is any respiratory change going on, then each cell must 
be living on its own supplies, for each cell-wall by dessication has 
become quite air-tight. Life may here fairly be described as 
anaerobic. 
If these dry cells in vacuo have really entered into a quiescent 
state in which no change whatever is taking place-—the state of 
“ static equilibrium ” as opposed to the “dynamic equilibrium” of 
the living ever-changing cell, then they should be capable of 
retaining their viability indefinitely. Time alone can settle this 
question and Becquerel has formally deposited seeds thus prepared 
in vacuo with the Bureau of Standards in Paris, and these are to 
be tested every ten years. Should they show no mortality, it is 
brilliantly suggested that then in this way standard plants may be 
handed down to remote posterity for comparison with the forms 
that evolution has produced in many generations of descendants! 
Till then, it is said, the question between these two theories 
must remain in abeyance. The reviewer would point out that in 
theory, gaseous exchange with the environment is not essential for 
an energy-liberating “respiratory” change within the cell. In the 
respiration of anaerobes no oxygen is taken in, while in the respiration 
of succulents no carbon dioxide is given out. We could imagine a 
combination of these attributes in such a change as the slow 
conversion of sugar into lactic acid C G H 12 O 0 =2 C 3 H G 0 3 by 
which a small steady supply of energy could be set free. Examination 
of the alteration of the cell-contents in seeds of great antiquity 
might give some clue. 1 
Becquerel’s final contribution to the elucidation of the discordant 
results of previous workers is to show that whereas quite dry seeds 
have no gaseous exchange, seeds that are merely air-dry, may 
conduct a continual, though slight conversion of oxygen into carbon 
dioxide. 
This is apparently a purely chemical oxidation, for, unlike 
respiration, it is increased by exposure to light, in particular blue 
light. Many carbohydrates are known to be slowly oxidised in 
sunlight in this way. Further Becquerel has shown that this 
oxidation is chiefly located in the testa, which when isolated, may 
alone account for as much CO a as the whole intact seed previously. 
Such chemical oxidation of the substances in the cells of the 
resting embryo might, in time, destroy the organisation needed to 
maintain viability, even if the organisation were, as regards vitality, 
in a state of static equilibrium all along. If this is so, then it is 
essential that critical tests on the longevity of seeds should be 
performed in the absence of oxygen as well as of water, which, 
indeed, is provided for in Becquerel’s standard experiments in 
vacuo. 
There is one line of experimentation in this field in which all 
workers have got concordant results. All are agreed that the 
vitality of ordinary dry seeds is quite unaffected by exposure to 
extreme cold such as that of liquid air (—190 n C) or that of liquid 
hydrogen (—250"C). 
1 Atpresent there seem to be only the observations by Acton, 
(Ann. Bot., Vol. VII., 1893) that old perished wheat contained 
more soluble constituents and less water than viable grains, 
