Centrifugal Force upon the Cell, 351 
distal end of the cell ; while oil and the vacuole, whenever 
the latter was present, occupied the proximal end. The oil 
formed a dense layer along the proximal transverse wall, and 
when present in sufficient quantities it filled the space between 
the vacuole and the corners of the cell. 
The Nucleus. 
To the writer, at least, one of the most interesting phases 
of the subject was that pertaining to the behaviour of the 
nucleus in root-tips of certain Phanerogams. Tips of the 
primary roots of Zea Mays, Vicia Faba , Allium Cepa , and 
Phasechts vulgaris were used. Of these, Zea and Phaseolus 
proved to be most satisfactory. 
The method of procedure was as follows. The seeds were 
allowed to germinate in moist sawdust, and when the primary 
root had reached a length of two or three centimetres the 
whole seedling of Zea was fastened by means of gypsum in 
a piece of glass tubing which had been widened out funnel- 
wise at one end. The seedlings were placed in the funnel so 
that the root passed freely into the tube while the body of the 
seed remained in the widened part. 
A thin batter of gypsum was now poured into the funnel so 
as to surround the seed but not to cover it entirely. The 
root was loosely wrapped with shreds of cotton close to the 
grain to prevent the gypsum batter flowing into the tube 
of the funnel. Fastened in this way, both root and shoot were 
left perfectly free, while the body of the seed was held secure 
and immovable so that not the slightest injury was received by 
the plant from the excessive weight of the seed during centri- 
fugal action. 
On account of the large size of the seed of Vicia , the whole 
seedling was not used. Root-tips about one centimetre long 
were cut off and inserted into tubes just large enough to admit 
them freely. The end of the root was then pushed a short 
distance into the gypsum batter which had been introduced into 
the end of the tube. The tip of the root thus rests in its own 
