This has produced the most extraordinary advance in medicine and biology. It has made it possible to determine the difference between healthy and diseased tissue; and not many years ago the microscope revealed the fact that the bodies of animals and men are the home of excessively small organisms called bacteria, some of which, through the poisonous substances they give out, cause disease. The modern treatment of many maladies, such as consumption, diphtheria, scarlet fever, and typhoid, is based upon this momentous discovery. The success of surgical operations has also been rendered far more secure than formerly by the so-called antiseptic measures which are now taken to prevent the development of bacteria.[464]
Scientific discovery and invention did not affect daily life before the end of the eighteenth century.
277. The discoveries of the scientist and of the mathematician did not begin to be applied to the affairs of daily life until about a hundred and fifty years ago. No new ways had previously been discovered for traveling from place to place. Spinning and weaving were still carried on as they had been before the barbarians overran the Roman Empire. Iron, of which we now make our machines, could only be prepared for use expensively and in small quantities by means of charcoal and bellows.
The 'domestic system' of manufacture.
Manufacture still meant, as it did in the original Latin (manu facere), to make by hand. Artisans carried on their trade with their own tools in their own homes, or in small shops, like the cobbler of to-day. Instead of working with hundreds of others in a great factory and being entirely dependent upon his wages, the artisan, in England at least, was often able to give some attention to a small garden plot from which he derived a part of his support. This "domestic system" was displaced by factories, as the result of a series of mechanical inventions made in England during the latter half of the eighteenth century. Through them machinery was substituted for hand and foot power and for the simple implements which had served the world for centuries.
Cheap iron and adequate power essential to the development of machinery.
Watt invents the steam engine.
In order that machinery should develop and become widely useful, two things were necessary. In the first place, there must be some strong material available of which to make the machines; for that purpose iron and steel have, with few exceptions, proved to be the best. In the second place, some adequate power must be found to propel the machinery, which is ordinarily too heavy to be run by hand or foot power. This necessary motive power was discovered in steam. The steam engine was devised by James Watt, an English inventor of great ingenuity. He invented a cylinder containing a piston, which could be forced back and forth by the introduction of steam. His progress was much retarded by the inability of the mechanics of his time to make an accurate cylinder of sufficient size, but in the year 1777 the new machine was successfully used for pumping. A few years later (1785) he arranged his engine so that it would turn a wheel. In this way, for the first time, steam could be used to run machinery—the spindles, for example, in a cotton mill.
Steam used for spinning and weaving.