550 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
notwithstanding ineffective disinfections and numerous removals of 
tenants, owe their danger to the presence of dried bacilli in the dust 
that is inhaled during sweeping. 
This persistence of vitality of cells may also be characteristic of 
tissues of the human body and may be advantageously utilized. This 
is what the splendid researches of Dr. Carrel are demonstrating to-day. 
This investigator, profiting by the experiments of Paul Bert, of which 
I have already spoken, has succeeded in preserving in a state of latent 
life certain tissues gathered aseptically from fresh corpses, such as 
fragments of skin, cornea, blood vessels, and bony tissues. These 
tissues protected from the air in sterilized vaseline at a temperature 
of 3° to 5° C. have preserved their vitality for 40 days, and conse- 
quently may be used for grafting. When some such method shall 
have been perfected it will render estimable service to surgery. 
Still other biological deductions result from the conservation of 
latent life, particularly when it is under the influence of low tempera- 
tures. For instance, germs arrested in their development may at 
this moment be subjected to the actions of complex causes which are 
determining their evolution. Borings made on continents covered 
with ice, such as the South Pole and the vicinity of the North Pole, 
where the temperature oscillates between 40° and 60° below zero, will 
perhaps permit us to gather seeds or old spores which have conserved 
their germinating power for many thousands of years under the action 
of the cold. 
Arrhenius goes still further in his deductions. He thinks that 
latent life is sufficient to enable germs to traverse the icy void of inter- 
stellar space intact during an almost unlimited period. To demon- 
strate it, the Swedish scientist has formulated his ingenious theory of 
interastral panspermism. I have already had occasion elsewhere to 
explain and discuss this hypothesis. 
Unfortunately, worlds can not be sown with germs in latent life, 
propelled by light from one to the other, because the action of the 
stellar ultra-violet rays in the center of the solar systems and even in 
the atmosphere of planets is too harmful, but also because there would 
be needed a very improbable concurrence of extraordinary conditions. 
So it is necessary to seek other modes for the propagation of germs 
in infinity. In advance of their discovery, there results from my 
researches upon latent life, from the point of view of the future of life 
on the globe, a conclusion which, notwithstanding its great proba- 
bility, will not fail to astonish us. This conclusion is that on the day 
when the sun shall be extinguished, when all the gases of our atmos- 
phere shall have disappeared, as took place on the moon, when active 
1 Paul Becquerel, La panspermie interastrale devant les faits: Revue Scientifique, Feb. 18, 1911, and 
C. R. Acad. des Sc., July 4, 1910. 
