Epidemic Respiratory DiseaseNote 21 — Chapter I · THE ETIOLOGY OF INFLUENZAReading editionOpie, Freeman, Blake, Small, and Rivers: Jour. Am. Med. Assn., 1919, lxxii, 108.◇Copy noteReturn to CHAPTER I THE ETIOLOGY OF INFLUENZAReturn to CHAPTER I THE ETIOLOGY OF INFLUENZA