Contemporaneous Physiology,' Presb. Quart. Rev., April 1876. Professor Tyndall gives a very graphic description of the combination of remarkable arrangements by which the human ear is fitted to be an organ of hearing. I quote from it the following words, and connect with them some striking observations of Max Müller. "Finally, there is in the labyrinth a wonderful organ, discovered by the Marchese Corti, which is to all appearance a musical instrument, with its chords so stretched as to accept vibrations of different periods, and transmit them to the nerve-filaments which traverse the organ. Within the ears of men, and without their knowledge or contrivance, this lute of 3000 strings has existed for ages, accepting the music of the outer world, and rendering it fit for reception by the brain. Each musical tremor which falls upon this organ selects from its tensioned fibres the one appropriate to its own pitch, and throws that fibre into unisonant vibration. And thus, no matter how complicated the motion of the external air may be, those microscopic strings can analyse it and reveal the constituents of which it is composed."--On Sound, p. 325. "What we hear when listening to a chorus or a symphony is a commotion of elastic air, of which the wildest sea would give a very inadequate image. The lowest tone which the ear perceives is due to about 30 vibrations in one second, the highest to about 4000. Consider, then, what happens in a _presto_, when thousands of voices and instruments are simultaneously producing waves of air, each wave crossing the other, not only like the surface waves of the water, but like spherical bodies, and, as it would seem, without any perceptible disturbance; consider that each tone is accompanied by secondary notes, that each instrument has its peculiar _timbre_, due to secondary vibrations; and, lastly, let us remember that all this cross-fire of waves, all this whirlpool of sound, is moderated by laws which determine what we call harmony, and by certain traditions or habits which determine what we call melody--both these elements being absent in the songs of birds--that all this must be reflected like a microscopic photograph on the two small organs of hearing, and there excite not only perception, but perception followed by a new feeling even more mysterious, which we call either pleasure or pain;--and it will be clear that we are surrounded on all sides by miracles transcending all we are accustomed to call miraculous."--Science of Language, second series, p. 115. The structure of the eye has often been described as an evidence of design. There is an extremely interesting comparison of it with the photographic camera in Le Conte's 'Religion and Science,' pp. 20-33. The whole reading public knows the masterly chapter on "The Machinery of Flight" in the Duke of Argyll's 'Reign of Law.' NOTE XIX., page 149. PSYCHOLOGY AND DESIGN.