Regarding these affections we possess numerous clinical, but only very few anatomic, reports; and there are practically no thorough and extensive microscopic observations. Below we shall give a short survey of the most important reports.

Among the earliest of these reports is the observation of Foa, who found numerous small hemorrhagic areas in the spinal cord. This disseminated hemorrhagic myelitis is analogous to our multiple focal hemorrhagic encephalitis grippalis. Under the title of "Acute Ascending, so called Landry's Paralysis," cases are reported by Fereol, Laveran, and Arcularrus. (Compare our remarks above concerning the similar picture presented by deceptive cases of very acute polyneuritis, p. 641.) A few cases diagnosed as acute anterior poliomyelitis are described by Chilarducci, Teissier, Henoch, and Drasche. Goldflam reports two cases of "superior and inferior polioencephalitis and anterior poliomyelitis." Numerous cases of paraplegia or parapareses of the lower extremities, occasionally with paralysis of the bladder, decubitus, etc., ran their course with the appearance of acute transverse myelitis or compression myelitis. Such cases of paraplegia have been reported by Deter mann, Liegeois, Herzog, Gross, Fiessinger, Maillart, Lacove, Revilliod, Admiraal, and Bossers. A paraparesis of the legs with ataxia is mentioned by Leubuscher, and a case of "myelomeningitis cervicalis with softening of the cervical cord" is described by Mackay. Maillart divides five cases of grippal disease of the spinal cord observed by him as follows: (1) Cases conforming to the type of transverse myelitis; (2) cases like "myelitide type tabes spasmodique." Such cases of "spastic spinal paralysis " of the lower extremities have also been observed by Revilliod and Herzog, who call them "disseminated myelitis." Leyden reports a case of disseminated encephalomyelitis with acute ataxia in a child, which terminated favorably. Remarkable cases simulating unilateral lesion of the spinal cord (Brown-Sequard paralysis) are described by Eulenburg and by von Determann from Erb's clinic. Peculiar transient paraplegias of the lower extremities, disappearing in from twenty four to forty eight hours, are described by von Vigla, and isolated paralyses of the bladder and incontinence of urine combined with "tremor of the lower extremities" have been described by Bilhaut.

The case described by us in 1890, besides many others described in literature, shows how complicated and difficult in the localization of the spinal affection caused by influenza*: A woman, forty nine years of age, had the following symptoms immediately after influenza: Girdle pains in the trunk and violent pains in both lower extremities; a weakness of the same with marked ataxia (incoordination); swaying of the body when the eyelids were closed; pupils quite normal; total paralysis of the bladder and incontinence of urine; cystitis; no sensory disturbances; increased patellar reflexes and lively ankle clonus. Recovery. This is a symptom complex which cannot be classified as peripheral neuritis, tabes, spastic spinal paralysis, nor transverse myelitis. It is one of those numerous peculiar indefinable clinical pictures arising from influenza and affecting more especially the cerebrospinal system.

We cannot here further discuss the numerous fragmentary observations of post influenzal myelitis, but we must not omit to state that many of these cases were no doubt due to neuritis or to functional, particularly hysterical, paralysis.

The remarkable influence on the nervous system exerted, as we have just seen, by the influenza process, was commented on already in earlier times (Graves, 1843; Vovart, 1880), and after our most recent epidemic especially led to extravagant pathogenetic definitions of influenza. It has been termed "central neural fever" (Glover) or a "vagus neurosis" which was made responsible also for the catarrhal and inflammatory manifestations of the respiratory apparatus, including the pneumonia.

A. Schmitz defines influenza as "an epidemic disease chiefly of the "nervous system," and Sell as "an infectious neurasthenia." Heidenreich in 1830 had called influenza "a disease of the ganglia with irritation of the mucous membranes." Althaus considers that all the symptoms are referable to nuclear irritation of the vasomotor centers, particularly of the pneumogastric nerve, by the influenza toxin. These hypotheses, while resting on a basis of correctly observed phenomena, miss the point because they ignore the action of the specific bacteria and their toxic products in directly causing the manifold organic lesions.

* Our influenza lectures, p. 28.