(2

Hofmeister ‒ Spirogyra

p 224) He measured the rate of growth of a cell under the microscope, & found the general character of the variations similar to the variation in the nutation. Short periods of rapid growth alternating with long periods of slow or no growth. In his table he makes several times over the cell get shorter instead of longer.

225 The movement of spirogyra is not so regular & constant in direction as that of Oscillaria He calls the tendency to creep up the sides of the vessel geotropic. He says they are also heliotropic

[sketches] Rough tracing of Hofmeister's drawing of the changes of a single filament

/over

[333v]

after giving De Vries.

But we think that something more remains to be made out & that no explanation can be considered as fully satisfactory, which does not include invisible organs, & these formed of a single row of cells. These circumnutate & bend to the light: Hofmeister found that the cell of Spirogyra which were then many many were not in a state of turgescence & he found that the growth of the cell-walls seems to followed the same general rule as the accord with the kind of movements, & this wd indicate that changes in the cell-wall play an important part in such movements.

In Chapter on circumnutation of mature organs.

The relaxation of cell-walls if in a state of turgescence in ca cell to bend over but H. says not in a state of [turgescence]

See to Vines in arbeiten(?) on part of Protoplasm in movements of mould.—

Are not the oscillating jerking movements of Hypocoty of cabbage & of Dionæa like the movements of Oscillaria.