18 
IOWA ACADEMY OF SCIENCES. 
Prescientific society was destroyed largely because it 
had attained no adequate means of defense. It is safe 
to say that had the Roman legionaries been equipped with 
Maxims and Mausers, the episode of the Hun and Vandal 
invasions of Southern Europe would have been indefinitely 
postponed. 
Modern society, which science has armed with the most 
terrible of death-dealing weapons, whose explosives are 
brought from the laboratory of the chemist, whose im- 
mense guns are fired at ranges which require the rotation 
of the earth to be taken into account, and with a precision 
which considers the difference in density of the air at the 
top and at the bottom of the bore, whose war ships are 
armored with the latest discoveries of metallurgy, their 
turrets turned and their guns loaded and trained by the 
electric current, and their evolutions directed by invisible 
vibrations of ether, — surely a society thus armed has noth- 
ing to fear from any barbarian peril, be it yellow or be it 
black. 
Civilization is safeguarded by science, not only from the 
irruption of savage hordes, but also from the invasion of 
disease, from such epidemics as that which in the middle 
of the 14th century swept away twenty-five millions of 
people in Europe, and more than half the population of 
England. Today when the plague appears in San Fran- 
cisco or in London, it excites no more alarm than Gibraltar 
would feel at the assault of Spaniard or Moor. By the 
simple remedy of vaccination, science has saved in each 
generation of the century more lives, it is said, than were 
lost in all the wars of Napoleon. Among civilized nations 
within the last five centuries the death-rate has been so 
lowered that the average duration of human life has nearly 
doubled. Medicine no longer attacks disease with charm, 
exorcism and nostrum; she obtains her weapons from the 
armory of science. From chemistry she brings a pure 
materia medica, new compounds, new processes, new 
methods of diagnosis, and anaesthetics which have made 
surgery painless. From physics she obtains the appliances 
of electro-therapeutics, a delicate cautery, and the Rcent- 
