Almost ten years have passed since the first human influenza virus was discovered, and there would be now no great difficulty in enumerating a long series of significant developments which have resulted from the many careful investigations of influenza carried out in the last decade. To do this, however, would place the present status of the influenza problem in a false light, since positive knowledge would be overemphasized and lack of knowledge considerably neglected. This seems a proper time and an unusual opportunity to attempt a brief appraisal both of those things which are known and of those which are not known about influenza.
As is so frequently true in investigative work, each of the major advances made in the development of a more complete understanding of influenza has left in its wake a number of unsolved problems. At the present time the more significant of these appear to be
HORSFALL FL. THE PRESENT STATUS OF THE INFLUENZA PROBLEMCLINICAL LECTURE AT ATLANTIC CITY SESSION. JAMA. 1942;120(4):284–287. doi:10.1001/jama.1942.82830390005010