That pneumococcic pneumonia is a contagious disease and that isolation procedures are necessary in the care of patients suffering from it have been emphasized by certain clinicians.1 Smillie and Leeder2 observed that 2 per cent of patients in contact with patients with pneumonia contracted pneumonia. In the report by Benjamin, Ruegsegger and Senior3 it was stated that 13 cases of pneumococcic pneumonia which were obviously due to cross infection occurred in the years 1936 and 1937 at the Cincinnati General Hospital and that during the following winter when isolation technic was enforced only two such instances of cross infection occurred.
Smillie4 has shown that type I pneumococcus is twenty times more prevalent in persons exposed to this strain than in the population at large. He stated, furthermore, that economic status and overcrowding play no role in increasing the number of positive contacts. The study of Benjamin,
GELLIS SS, MITCHELL AG. CROSS INFECTION WITH TYPE I PNEUMOCOCCUS. JAMA. 1941;116(23):2580-2581. doi:10.1001/jama.1941.02820230024007