of the forenoon is seen well illustrated in the above record (Fig. 26).
Fig. 26. Morning record from 8 a.m. to 12 noon, exhibiting gradual enhancement of excitability.
The record of daily periodicity given in Fig. 23 may be regarded as a typical example. Modifications may, however, be observed which are traceable to individual peculiarities. As an example of this, I give a record (Fig. 27) obtained with a specimen in which nyctitropic movement was very pronounced. The periodic variation of excitability exhibited here is practically the same as shown by other specimens. The interesting variation is in the character of the recovery from stimulus; the leaf was falling from 6 to 9 p.m.; owing to the shifting of the base-line upwards the recovery appears to be incomplete. After 9 p.m. the leaf was erected, at first slowly, then at a very rapid rate. The consequent fall of the base-line late at night is very abrupt; hence there is an
