We seldom see among the lists of "patents sealed" and "provisional protections" granted, any reference to an invention for improvements in the mechanism of parrots and cockatoos. It is a remarkable thing that so obvious a field for invention and improvement should have been so much neglected. Plainly, an easy and obvious improvement would be the provision of a simple shut-off valve, by which the suffering proprietor could stop the parrot's steam whistle when desired. The desirability of some such improvement need not be enlarged upon, and, once the appliance were in the market, every parrot-owner would hasten to have it fitted to his machine. Another contrivance, having the same object, would consist of a self-acting escape valve, by which the familiar scream of the mechanism would be diverted, and escape noiselessly through a small grating at the back of the neck after a certain degree of pressure had been attained. Moreover, what more easy than to have the outer side of the jaw-hinge fitted with a convenient butterfly-nut, by tightening which, after the periodical stoking with maize and so forth, the engine would be prevented from nipping carelessly-offered fingers? As it is at present, the jaw-hinge is a mere ordinary pair of sharp pincers barbarically ornamented with feathers and colours. Improvements suggest themselves at every point. Many of these otherwise amusing instruments cause trouble by occasionally breaking out into startling and exceedingly forcible language. It would seem that a pressure valve might be profitably employed in this case also, by means of which, as soon as the expressions reached to the degree of "blow it," or "shut up," the power would be immediately diverted, and either allowed to escape harmlessly through a small chimney at the top of the head, or else conducted by a power-transmitting mechanism to an adjacent musical-box, which would play "Pop Goes the Weasel," or something else of a similarly moral tendency. The whole subject is full of profitable suggestions, which are offered, free of any expense beyond a small royalty to myself, to the notice of persons of mechanical genius. [Illustration: A MERE] [Illustration: PAIR] [Illustration: OF PINCERS.] _Stories from the Diary of a Doctor._ _By the Authors of_ "THE MEDICINE LADY." IX. AN OAK COFFIN.