In 1973, he discovered the dendritic cell - so named because it has little tails, like dendrites in neurons - and set about explaining their function.

And what they saw is a steady decrease in the size and number of dendritic spines, the tiny branches of the nerve cell that receive messages from nearby cells.

From this description, it is clear that Dieters easily differentiated between the dendrites and the axon, but that he did not know if the axon arose from the cell body or from the dendritic tree.