While there seems little doubt that meteorological conditions have a distinct influence on the occurrence of pneumonia, and although a good deal of investigation has been carried on in the endeavor to throw light on this relationship, yet there is still a considerable lack of unanimity of opinion in our present views regarding this connection.
Concerning the relation of season to pneumonia, it is apparent that the greatest incidence from this disease occurs during the cold months. Seitz1 showed that for a period of twenty years in Munich, 37 per cent. of the cases occurred in the spring, 32 per cent. in winter, 16 per cent, in autumn and 15 per cent, in summer. Anders2 found the incidence in Philadelphia for a period of ten years to be: first quarter, 43.2 per cent.; second quarter, 24.5 per cent.; third quarter, 9.6 per cent., and fourth quarter, 22.8 per