Abstract
The gradual descent of poliomyelitic infection, after intranasal inoculation, through the olfactory tract, the basal ganglia, midbrain, pons and medulla to the spinal cord was demonstrated in experimental animals (monkeys) by Faber and Gebhardt, 1 using the method of recovering virus from bits of nervous tissue excised on successive days of the preparalytic period. Evidence was presented by Faber 2 that the infection in man may follow a similar pathway. Since this method of recovering virus permits only a rough localization, other means were sought to obtain a more precise definition. Evans and MacCurdy 3 reported successful vital staining of poliomyelitic lesions in monkeys, but failed to state the dye used or the period of infection when the animals were examined. McClellan and Goodpasture 4 were able, by means of intravital staining with trypan blue and subsequent clearing of the tissues, to visualize the lesions of another axon-conducted viral disease, herpetic encephalitis. Their method has been used in the present study of the sites and character of the lesions in the preparalytic stage of experimental poliomyelitis after intranasal inoculation carried out by the technic of Schultz and Gebhardt. 5 †
Results in 3 rhesus monkeys are here reported: 1. a control; 2. an animal killed 3 days after inoculation; 3. an animal killed 6 days after inoculation, before paralysis or weakness occurred.
In the control, which was given no inoculation with virus but received trypan blue in the same manner as the inoculated animals, there is no visible staining of the nervous tissues proper. The dura, velum interpositum and choroid plexuses are deeply stained, while the leptomeninges are faintly stained. The smaller arteries and veins are inconspicuous and there is no evidence of capillary dilatation.
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