The value of respiratory re-education in the treatment of convalescents was pointed out recently (1905) by M. Siredey and M. Rosenthal in a paper read at a meeting of the Société Medicale des Hôpitaux. An excerpt from the _Lancet_, February 18, 1905, p. 463, reads as follows: “They said that respiratory insufficiency was one of the causes of the general debility which showed itself after an acute illness. It was easily recognised by the following symptoms, which the patient presented, namely, thoracic insufficiency, shown by absence or impairment of the movement of the thorax; and diaphragmatic insufficiency, shown by immobility or recession of the abdomen during inspiration—a condition met with in pseudo-pleurisy of the bases of the lungs. “Respiratory re-education was, in their opinion, the specific treatment for respiratory insufficiency. In the case of convalescents it constantly produced a progressive threefold effect, namely, expansion of the thorax, diuresis, and increase of weight. It promoted in a marked degree the recuperation of the vital functions which followed acute illness, and the general health of the patients improved rapidly. It ought to be combined with other forms of treatment, and the action of the latter was enhanced by it.” The matter of preventing defective and restoring proper action clearly calls for attention. The foregoing will enable the reader definitely to understand what is necessary, viz., 1. In _Prevention_. The inculcation of a proper mental attitude towards the act of breathing in children, to be followed by those detailed instructions necessary to the correct practice of such respiratory exercises as will maintain adequate and proper use of the breathing organs. 2. In _Restoration_. A body possessing one or other or all of the defects previously named will need re-education in order to eradicate the defects brought about by bad habits, etc., and to restore a proper condition. As the breathing mechanism is ordinarily _unconsciously_ controlled, it is necessary, in order to regain full efficiency in the use of it, to proceed by way of _conscious_ control until the normal conditions return. Afterwards, when perfected, unconscious control—as it originally existed prior to respiratory and physical deterioration—will supervene. II ERRORS TO BE AVOIDED AND FACTS TO BE REMEMBERED IN THE THEORY AND PRACTICE OF RESPIRATORY RE-EDUCATION “Each faculty acquires fitness for its function by performing its function; and if its function is performed for it by a substituted agency, none of the required adjustment of nature takes place; but the nature becomes deformed to fit the artificial arrangements instead of the natural arrangements.”—HERBERT SPENCER.