1. Observations have been made on marmots paralysed by the attachment of the ixodid tick Dermacentor andersoni Stiles.
2. Acetylcholine synthesis by excised tissues from paralysed animals is unaffected.
3. Conduction in both motor and sensory nerve fibres is markedly reduced. It is likely also that the excitability of neurones of the spinal cord is diminished.
4. There are changes in the electrocardiogram suggestive of a slowed rate of auricular and ventricular depolarization and repolarization.