But even as late as 1800 A.D., in spite of the mariner’s compass, the printing press, and gunpowder, the ground won by Hephæstus was very small. The postal services in Europe were inferior to that of the Cæsars, there was no telegraphic system equal to that of the ancient Persians, and the most stately sailing ship barely excelled the classical trireme. The fruits of the work of Newcomen and Watt and Papin had not yet blossomed. When they did come forth, things happened swiftly. Fire was made to generate steam, and steam, in the course of a century, transformed the world. The motive-power being there, it was put to a million uses. The Wheel became the most important of mechanical contrivances. Now a wheel is a thing which, in the organic world, is simply impossible. In the days when microscopes were of feeble power, it was thought that the “wheel animalcule,” called _Vorticella_, had small wheels revolving on the rim of its opening to gather in the floating food particles. But higher magnifying power showed that the appearance was an illusion created by the oscillation of the fine hairs fixed round the aperture. A wheel revolving on a shaft implies a separation which precludes all organic connection. Had it been otherwise, an animal running on its own wheels would have made its appearance on earth long ago. The shaft of the steam engine could be provided with numerous pulleys, each capable of driving a machine connected with it by a belt. Then arose that marvellous crop of mechanical combinations which brought about the age of mechanism, combinations which, in the last resort, can be reduced to sliding couples and turning couples, and can be catalogued by means of formulæ, like words in a dictionary. So numerous were these inventions, so widespread was their use, and so great their effect on the minds of those generations, that a great illusion arose which coloured the philosophies of a whole century and has left traces even in modern times. People became so accustomed to the perfect functioning of a machine or a clock, so impressed with its regularity and intelligible complexity, that they began to look upon mechanism as a primary thing capable of “explaining” many non-mechanical things, not excluding the phenomena of life. Why should not man himself, the inventor of machinery, be a machine? If any functions of his body seemed beyond explanation on mechanical lines, might this not be solely due to their great complexity? In a recent article in _Nature_, Professor Fraser Harris puts the matter tersely as follows: “Because the stomach ‘works’ rhythmically and predictably we may call it a machine for turning out pepsin from blood and liken it to a machine for turning out (say) newspapers, but the secretion of pepsin is not mechanical, nor is the output of newspapers vital.”