Pneumonia in the new-born

It is only within comparatively recent years that the prevalence of pneumonia among new-born infants has begun to be recognized. Since the work of Hess- Thaysen (1914) first called attention to the great frequency of this disease, several workers (Browne, 1921, 1922 ; Johnson and Meyer, 1925 ; Cruickshank, 1930 ; Chase, 1935) have published the results of investigations of large series of cases, all proving that pneumonia is one of the principal causes of neonatal death. In spite of this it is probable that its great frequency has not yet been fully realized. This is largely due to the difficulty of clinical diagnosis, which is such that the vast majority of cases are not recognized unless a necropsy is performed, and even then, in many cases, only if the pathologist has experience of neonatal pathology and takes special care. As a result, the prevention of this disease receives in many quarters less attention than it deserves. This may be explained in part by a lack of clear knowledge of the causes and patho- genesis of neonatal pneumonia, for in spite of a considerable amount of patho- logical study much doubt and disagreement still exist as to the mode of infection, the relative importance of infection received before and after birth, the principal causative bacteria and on other fundamental questions. In particular, an extensive study of the literature showed that little attention has been paid to pneumonia developing after the first few days of life, and that knowledge of the bacteriology of all types of pneumonia in the neonatal period is surprisingly scanty.