LATENT LIFE: ITS NATURE AND ITS RELATIONS TO 
CERTAIN THEORIES OF CONTEMPORARY BIOLOGY. 
By Paut BecquEREL, Sc. D. 
I. GENERAL OBSERVATIONS. 
Although the study of latent life holds an unimportant place in 
most of the standard works on biology, yet it is none the less one of 
the most widespread phenomena of the living kingdom. We meet 
it everywhere that germs exist. And since germs are continually 
emitted in considerable quantity, even more by plants than by ani- 
mals, there is not a piece of ground on which we tread nor the smallest 
quantity of air that we breathe which is free from them. 
Not only can the spores of fungi, bacteria, algz, mosses, and of 
ferns, the myriads of grains of pollen from flowers, the seeds of 
phanerogams, the cysts of infusoria, the eggs of certain crustaceans 
and insects, pass into a state of latent life, but likewise animal tissues, 
and even some perfectly developed forms of life called reviviscents, 
as certain species of alge, mosses, lichens, rotifers, arctisca, and 
nematodes. 
In that condition of repose, these germs or beings may escape the 
harsh necessities of active life, better resist dryness, cold, or heat, are 
more easily carried away by the currents, winds, or other causes, 
finally to await for several years the return of conditions favorable 
to their development. 
II. THEORIES AS TO THE NATURE OF LATENT LIFE. 
But what is the true nature of latent life? Is it apparent death in 
which all the vital functions are suspended; is it a relaxed aérobic 
life demanding gaseous exchanges with the atmosphere, or is it a ° 
very sluggish, intercellular anaérobic life? These are questions which 
since the beginning of the eighteenth century have engrossed the 
attention of eminent naturalists, have incited numerous experiments, 
and which at this moment provoke interesting controversies. 
We owe to Leeuwenhoek (1701), the founder of micrography, the 
first observations on reviviscent animals, the arctisca or water bears, 
and rotifers of the roofs and gutters. That author observed with 
1 Translated by permission from Revue générale des Sciences pures et appliquées, vol. 25, No. 11, Paris, 
June 15, 1914, 
537 
