[71]

Apheliotropm Mustard — Caustic

In the experiments on Ap 29 & 30, 14 15 were causing cauterized; & of these 12 were not apheliotropic, 2 were apheliotr & one doubtful

Caustic 18 [+] 23 [=] 41

Of All the 18 control roots were apheliotropic

The cauterized roots grew well— ie increased by from 5 to 7 mm in 8 or 9 hrs—

Ap 29 was bright sunshine, Ap 30 was "gleams of sun"

25 [+] 16 [=] 41 16

In the experiments Sep 7, 12 & 13, 41 roots were cauterized of these 25 were apheliotr, 16 were not so. All 20 23 controls were apheliotr except 2 doubtful & apheli ones. These jars were put to a North light, but the temperature was sufficiently high viz 16 C in the morning

Adding the Sept & April experiments together there are 53 54 cauterized ones whose of which 25 are Aph, 28 not so, & one doubtful. Of 41 controls, 39 are aphelio: & 2 doubtful

On Sep 12 & 13 the seedlings were examined in the evening & there was neither heliotr of the stems nor apheliotr of roots, the curvatures recorded in above experiments appeared during night & the following morning; the seedlings were in both experiments examined between 10 & 11 on the morning after they had been cauterized

They were all grown in sawdust till taken out to be cauterized & grown in water in glass jars

[71bis]

In the April experiments the bending place was at about 4 mm from tip.

The blackened tips were about 1/2 mm, or rather more eg 0.7 mm

I am not sure about the colour of the tips

[71v]

How treated — How much blackened or browned Kept in water or out

we may therefore conclude that sensitive to light reside in the tips of the radicles of S. alba whereas all other & that it travel some [illeg] way to induce the bend for a time of about 4 m. in the same manner as we have seen sensitiveness to caustic & other irritant reside in the tips of — radicals of vars plants, & as we shall presently see in the next chapter that is likely the case in the seniti sense of gravitation.