The first and probably the most interesting and confusing are the conditions found in the lungs following influenza. A chronic bronchitis, an old bronchiectasis, or a previous tuberculous lesion in whatsoever stage, may present acute symptoms and signs which are difficult to interpret. The question always arises in the individual case—is this a process due to the recent influenzal attack, or was it there before the attack? Is it of streptococcic, pneumococcic, or tuberculous origin? The history of previous diseases of the lungs may help to arrive at a diagnosis. The history of the severity of the influenzal attack is of very little help, because the apparently mildest attack may be followed by the most profound changes in the lungs, and the gravest attack with a history of definite lung infection may leave the lungs without a trace of the previous pathology. The physical examination is helpful, of course, in determining whether the lesion is at the apices or at the bases, and from this a reasonably safe inference may be drawn as to whether it is from a previous tuberculous lesion or a recent influenzal infection. The Roentgenologist depends almost entirely upon this localization. If the linear striæ are only at the apex, it is probably tuberculous; but if they are only at the base, or also at the base, it is likely to be an influenzal lung. In fact, the Roentgenologist with his present information is ready to admit that it is most difficult to speak definitely of the lungs in these cases. The possibility of confusing the post-influenzal lung with a tuberculous lesion is not peculiar to this epidemic. After the epidemic of 1889 and 1890 the same condition was observed by clinicians. Dr. Roland G. Curtin, of Philadelphia, in 1892 and 1893 conducted a series of clinics at the Philadelphia Hospital, in which he spoke of the “non-bacillary form of phthisis,” and showed case after case which he said might be diagnosed as pulmonary tuberculosis, but because of the recent epidemic and the absence of the tubercle bacillus he diagnosed them as post-influenzal lung. In the present stage of our knowledge, many of these post-influenzal lungs will not be diagnosed properly until sufficient time is given for either the lung to clear up or the tubercle bacillus to appear in the sputum. We would emphasize the importance at the present time of finding the tubercle bacillus in all suspicious lung lesions before giving a positive opinion as to the tuberculous nature, even though the physical signs are very definite. Another group of sequelæ is that due to thyroid disturbance, or disturbance of the endocrin system in general. Since the epidemic a number of patients have been seen who noticed an enlargement of a previously normal thyroid gland or greater enlargement of a previously hypertrophied gland. In the same way the symptoms of hyperthyroidism appeared, new in some or a recrudescence in others.