sap that nourishes them, being heavy, tends downwards more than upwards; and again, because those [branches] which grow downwards turn away from the shade which exists towards the centre of the plant. The older the branches are, the greater is the difference between their upper and their lower shoots and in those dating from the same year or epoch.
[Footnote: The sketch accompanying this in the MS. is so effaced that an exact reproduction was impossible.]
398.
OF THE SCARS ON TREES.
The scars on trees grow to a greater thickness than is required by the sap of the limb which nourishes them.
399.
The plant which gives out the smallest ramifications will preserve the straightest line in the course of its growth.
[Footnote: This passage is illustrated by two partly effaced sketches. One of these closely resembles the lower one given under No. 408, the other