544 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
of 1819, Cytisus biflorus of 1821, Leucena leucocephala of 1831, and 
Trifolium arvense of 1838. The seeds which germinated at such an 
age were covered with a very thick tegument, whose impermeability 
to gases was checked experimentally in the case of the Leguminosz 
and the Nelumbonacee. In this way it was proved that some seeds 
conserved their germinative power from the epoch of the Restoration 
to our time without their embryo having gaseous exchanges with 
the atmosphere. The tegument of these seeds preventing through 
the years the oxidation of the substances in reserve and their hydra- 
tion under the action of the humidity of the atmosphere, did much 
to assure them this remarkable longevity. 
Nevertheless, this longevity is not unlimited. The germinative 
power always diminishes with time. Macrobiotic seeds, to use the 
picturesque expression of Ewart, who has written an excellent mon- 
ograph on them,’ do not keep their germinative power much beyond 
a hundred years. 
The claim of Claude Bernard that the latent life of seeds, under 
natural conditions of their preservation, is not exhausted, rests on 
inexact data, and the undeniable fact of the aging of commercial 
seeds seems to refute it. When, however, you carefully examine the 
significance of this fact, it is not a positive proof against the theory 
of suspended life. The loss of the germinative faculty of the seed 
may very well be caused by physico-chemical phenomena which may 
not apply to those of an extremely sluggish life. 
Why should not the protoplasm of the cells, when life is suspended, 
become decomposed in the course of time under the influence of the 
humidity and the oxygen accumulated in the intercellular spaces ? 
What would prevent its comporting itself like inert substances which 
gradually lose their original properties, their potential energy? With 
time liquors are modified, a sprmg tends to wear out, powder ages, 
and yet in these substances there is no retarded life! 
VI. THE DEHYDRATION OF GERMS. 
However that may be, since it is impossible to prove that a seed 
preserved under ordinary conditions is in a state of suspended life 
rather than in one of relaxed life, the problem might perhaps be 
solved by placing the seed under artificial conditions such that, with- 
out affecting its germinative power, its life may be temporarily 
arrested. 
_ All the writers who are engaged with this subtile problem are of 
the opinion that the water and the gases inclosed in protoplasm are 
the cause of its decomposition. A seed in a state of natural desicca- 
tion always contains a quantity of water ranging from 0.5 to 20 per 
! Ewart, On the longevity of seeds. Proc. Roy. Soc., Victoria, vol. 21, 1908. 
