16 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 

 w^hich 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 aneesthetics which have made 

 surgery painless. From physics she obtains the appliances 

 of electro-therapeutics, a delicate cautery, and the Roent- 



