20 IOWA ACADEMY OF SCIENCES. 



Micro-biology extends her aegis also over the herds and 

 crops of man. She destroys the insect enemies of our 

 grain fields and protects vine and fruit tree from blight 

 and mildew^. She saves the silk worms of Europe from 

 the plague which threatened their destruction, and the 

 flocks and herds of America from some of their most 

 destructive diseases. In twelve years the application of 

 Pasteur's inoculations saved France seven million francs 

 in the item of anthrax, and reduced the mortality of hog 

 erysipelas from 20 per cent to 1.45 per cent. 



Thus science performs a service to society incalculable 

 in its value. It defends it from foes, both within and 

 without the gates. It prolongs life, assuages pain, lessens 

 disease, and makes death a euthanasy. So notable have 

 been its victories during the century that we may almost 

 prophesy the speedy coming of the time when the only 

 deadly bacillus remaining will be that as yet undescribed 

 species of bacillus senectutis, or at least when only suffi- 

 cient of disease will be left on earth to provide for the 

 speedy and a beneficent extirpation of the unfit. 



Viewing organic evolution from the angle of the physi- 

 cist and considering the animal body simply as a machine 

 for the transformation of potential into kinetic energy, the 

 secular process sums itself up in the production of better 

 and better machines. From the fish of the early Paleozoic 

 on to the amphibian of the Carboniferous, the reptile of 

 the Mesozoic, and the mammals of the Tertiary and of the 

 present, we have a series of higher and higher organisms, 

 each capable of doing more work and better work than its 

 predecessors. 



It is possible to construe social evolution in the same 

 terms. Primitive society was weak. The energy at its 

 disposal was that only of the human body, the beast of 

 burden, and to a limited extent, of wind, water and flame. 

 So feeble was the ancient state in what may be termed its 

 musculature, so little could it utilize the forces of nature, 

 that it may be compared with a stage of organic evolution 

 preceding that of the vertebrata, that, let us say, of the 



