_Respiratory Diseases_ 6. In the group of respiratory diseases I think we should include a number of diseases not commonly regarded as such, but in which, so far as can be judged, infection is received by inhalation; and I would, therefore, group together such miscellaneous diseases as poliomyelitis, cerebro-spinal fever, measles, bronchitis, pneumonia, and influenza. All agree in one particular, that attempted preventive measures against their spread are dubious in effect. These diseases naturally divide themselves into two groups: the first comprising measles and influenza, both of which spread—when, as in influenza, the almost unknown conditions determining spread are present—to an extent only limited by the failure of susceptible persons; and the second comprising the other diseases already enumerated, of the conditions determining attack from which we are profoundly ignorant. We do know, however, concerning cerebro-spinal fever and measles, that they spread more easily and become more severe under conditions of massive overcrowding; and their unusual severity in war is thus partially explained. Beyond this obvious indication for prevention we can do but little. It may, however, be mentioned, that in England during the last few years, we have determined that our lack of ability to prevent outbreaks of measles shall not prevent us from attempts to _diminish their fatality_, and the notification of this disease has therefore been enforced, as a necessary preliminary to prompt and fairly complete action, and local authorities have been urged to provide nurses to assist in the domiciliary nursing of cases of measles. Grants of half the expenditure expended in nursing this and some other children’s diseases are paid by the Central Government. If the spread of infection cannot be stayed, it is our duty to diminish the loss of life by providing nursing assistance whenever required. This provision of nursing assistance in a number of children’s and maternal illnesses, half the expenditure being paid from Central and half from local funds, will, I trust, soon be followed by a general provision of nursing assistance from public funds. The recent epidemic of influenza has taught us several important lessons—First, we have been painfully reminded that we are completely ignorant of the causes of the pandemic waves of this terrible disease, which, at irregular intervals of years, traverse the world. We may surmise that the crowding and the mental and physical depression of war caused increased rapidity of spread and a greater fatality in the present outbreak; but influenza has spread and been only less fatal than in the present outbreak when there was no war, and we must admit our ignorance of the cause of this.