firm the view which we had previously stated and to which Romer and Kraus lent their authority, viz., within the organism the virus travels along the nerves, undoubtedly by way of the accompanying lymphatics. As what we have experimentally shown frequently occurs in accidental infections in man, these observations may be of importance in enabling us to determine the path of infection in human beings."
Landsteiner and Levaditi, by successful inoculation of the anterior chamber of the eye, and also by demonstrating that inoculation through the nasal mucous membrane renders the olfactory bulb virulent, have further established the probability that the nerves are the conducting channels for the virus.
As a control experiment Leiner and v. Wiesner clamped the sciatic nerve in an animal and injected the virus into the nerve distal to the clamp. They then thoroughly isolated and ligatured the nerve at the point where it had been clamped. Poliomyelitis did not follow the inoculation; the animal remained healthy.
Krause and Meinicke, contrary to other experimenters, assert that infection occurs through the blood stream; or, at least, that at a certain stage, a blood infection occurs. They actually found the blood and spleen of children, who had succumbed to infantile paralysis, contained the virus. Other investigators have failed to demonstrate the poison in the blood of infected monkeys.
The foregoing observations seem to add experimental ratification to the doctrine of lymphatic infection which I enunciated. Against this doctrine are two facts: first, that intracerebral inoculation may cause paralysis which sets in first in the lower extremities, and, second, that experimental poliomyelitis may be produced by intravenous injection.
Concerning the first, investigation is still being made: Leiner, Wiesner and Römer have already shown that here no essential contradiction necessarily exists.
Concerning the second, I think we must clearly distinguish between the way in which the poison reaches the spinal cord and the mode in which the changes of poliomyelitis originate. These are by no means one and the same. Let us take an elementary example. Suppose a certain amount of virus settles in, for instance, the region of the posterior horn. The changes which here occur produce no picture typical of the disease. If, however, the
