||P.627 bottom paragraph:"The reality of both fast and slow components of axoplasmic transport in nerve fibres is generally accepted (Lubinska, 1964 Barondes, 1967
Grafstein, 1969 Ochs, 1969), but uncertainty exists about the rate of the fast component. Rates given for fast axoplasmic transport range from
50 to over 2000 mm/day (primary sources). In part, this spread is due to the lower rates found in nerves of the invertebrate and lower vertebrate (Grafstein, 1969 Davison, 1970 Fernandez, Hunees & Davison, 1970) as compared to the mammal. Variations are also due to differences in the techniques used to determine rate."