170 THE JOURNAL OF BOTANY 
mena of protoplasmic movement which m8 be cating referred to 
physical and chemical causes; and ‘‘ Physiology,” which 
the author deals with those so- -alled vital phenomena for which it 
i sible to fin 
between streaming, assimilation, and al owth, the influence 
of the nucleus, and the effect of various external stimuli on the 
process. 
The author concludes that the energy of movement is generated 
in the moving layers themselves, which _ retarded by ng 
against the non-moving ec ent and als ut to a much les 
extent, by friction against the cell sap. The velocity of sitccmie 
osmotic pressure has little or no direct influence Meae! the process. 
Gravity exercises little or no influence upon streaming in sma 
cells, and only a very slight effect in the case large cells; 
bjec 
(8) the duration of the exposure ; (4) the supply of oxygen; and 
trong light re tards strea aming, wile eak light may indirectly 
accelerate ~ process in shicocley becaialinna cells. ae ids, 
a d metallic poisons all retard the process, and may cause 
porary shock-stoppage when suddenly applied. — sochols 
ont “anventhetics — weak electrical currents may accelerate the 
centrated solutions and strong fie retard it. 
The eboroplasts have no active power of movement, but are carried 
passively in the stream. 
ys antase pone energy _— the only kind of energy 
treamin 
: ae appendix on the electrical: speeioy? of egg albumin was 
not included in the original paper. 
A. Bu 
