Careful meteorological observations and records kept in Chicago during the prevalence of the epidemic of 1889-'90 showed the presence in the air of a de cided excessive amount of both free and albuminoid ammonia, with almost entire absence of ozone. Whether such condi tions of the atmosphere could foster the rapid evolution of the bacillus of Pfeiffer could be determined only by similar rec ords kept through both epidemic and non-epidemic periods. That the disease is caused by some infectious or bacterial agent, capable of rapid development and wide diffusion in the air, is proved by the suddenness of its attack, the large num ber attacked at the same time in a com munity without any communication with each other, and its simultaneous out break in places widely separated from each other. Thus, in the last great epi demic, beginning in the autumn of 1889, it was recognized in St. Petersburg in October, in Central Europe in Novem ber, and in England, Massachusetts, Con necticut, New York, Pennsylvania, Ehode Island, Ohio, Indiana, Illinois, Wisconsin, and Kansas during the last week of December, 1889 (see Jour. Amer. Med. Assoc., volume xiv, pp. S17-822). To the same import is the fact that the passengers and crew on board of ships have been attacked on the ocean two weeks after any communication with the land. And also the fact that hermits and other persons in complete isolation have suffered severe attacks at the same time with those in the general commu nity. The bacillus discovered by Pfeiffer, and claimed to be the essential cause of influenza, is very small, non-motile, and stains well with methylene-blue.
It is found in great numbers in the nasal and bronchial muco-purulent dis charges during the active progress of the disease, and sometimes remains in those localities several weeks after the recovery of the patient. It has been found pene trating other tissues and in the blood, though much less abundantly, and on culture-media it is said to grow only in the presence of hEemoglobin.
Pathology.—Ordinary post-mortem ex aminations reveal no structural changes peculiar to this disease. There are con gested and inflammatory conditions of the mucous membrane either of the re spiratory passages or of the digestive or both. In some cases such a inflammations have extended into the frontal sinuses, the maxillary antrum, and to the middle ear, and in more cases there are evidences of pneumonia.
Hmmorrhagic otitis media described as characteristic of the epidemic. It sets in between the third and seventh day of the disease, and is attended with limmor rhagic effusion into the tympanum, mani fested by intense pain. Spontaneous per foration usually takes place in the course of twelve hours. Hang (Mtinch. Med. Woch., Jan. 21, '90).
One hundred cases of aural and cu taneous complications seen in epidemic of influenza. Although very painful, the patients spending sleepless days and nights from the agonizing pains shooting through the head and shoulders, the cases, as a rule, ended in complete re covery in a comparatively short time.
Eitelberg (Brit. Med. Jour., July 19, '90).
Ocular lesions seen in influenza are manifold, but, if any predilection is shown, it is for the optic nerve and ret ina, and for the various periorbital sinuses. In panoplithalmitis enucleation should be deferred when the infection is from a general cause and the patient is in bad condition; but when the origin is local and the general condition is good it should be performed at once. Panas (Revue Gen. de Clin. et de Then Jour. des Prat., Apr. 20, '95).
Eye complications following grip are comparatively rare. Grip may affect the eye by inflammatory process or by inva sion of the accessory sinuses. It may affect the nervous tissues. The inflam matory affections involve especially the conjunctiva, the uveal tract, tissues of the orbit, and perhaps the fibrous cap sule of Tenon. The nervous apparatus of the eye is especially liable to become involved by paresis of accommodation or of the extrinsic muscles of the cervical sympathetic, by papillitis and retrobular neuritis, and also anmsthesia of the cor nea may occur. Pooley (Amer. Jour. of Ophthal., May, '95).
The presence of the influenza bacillus exerts a very unfavorable influence on the bony structures of the ear, often con verting apparently very simple cases of acute suppurative otitis into very malig nant ones, with rapid destruction of bone, and this without marked symptoms. This tendency to rapid bone-destruction should be constantly kept in mind, and can be prevented only by early and, if necessary, repeated paracentesis. Wells P. Eagleton (N. Y. Med. Jour., Aug. 7, '97).
Influenza is primarily a local parasitic disease of the mouth, throat, bronchial tubes, etc., the special nervous symptoms being due to absorption of the toxin se creted by Pfeiffer's bacillus. This toxin exerts a selective affinity for different parts of the nervous centres, with a strong tendency to largely affect the medulla oblongata. In the spinal cord the sensory appear to be more affected than the motor portions, shown by the numerous special painful affections seen in eases of the disease. The so-called incubation-period, of hours or two or three days, is that in which the first por tion of this toxin is formed, and this often takes place before any sensation of illness is felt. The effect upon the nerv ous tissue unquestionably varies from mere poisonous irritation to actual in flammation, and the seriousness of the effects will vary with this. One of the best proofs of the special involvement of the bulb and the eighth nerve is the marked influence exerted upon the heart, as shown by the marked and often fatal asthenia observed in acute cases; also by the tachycardia and bradycardia seen in connection with the influenza] disease. Peter Eade (Brit. Med. Jour., Sept. 29, 1900).