No. 460.] STUDIES ON PLANT CELL.— V. 227 
protoplasm outside of the cell walls, but connected with the 
cytoplasm within through fibrille. The intercellular proto- 
plasm is thus conceived in organic connection with nucleated 
cells and from the studies of Townsend (97) we know that non- 
nucleated protoplasm may live so long as it is united with 
nucleated, even though it be by very delicate fibrille. Michnie- 
wicz (:04) confirms Kny's conclusions for Lupinus and gives a 
very clear account of the fibrille which connect the masses of 
intercellular protoplasm with neighboring protoplasts. These 
studies make clearer a number of observations of several inves- 
tigators (Sauvageau, Buscalioni, Schenk, Magnin, Strasburger, - 
and others) who have noted similar conditions in the tissues 
of higher plants which are being investigated in detail by Kny. 
Some of the lower unicellular forms likewise exhibit an extra- 
cellular surrounding film or envelope, which may also be of a 
protoplasmic nature and consequently in the same position in 
relation to the protoplast as intercellular protoplasm. Thus it 
has been known for many years that the cells of the Peridinales, 
diatoms, and desmids possessed extracellular material, which 
some authors have considered in the nature of slimy excretions 
but others — Schutt ('99; : 00a; : 00b), Hauptfleisch ('88 ; '95), 
Müller ('98—99) — have regarded as protoplasmic in character. 
Since the cell walls in these forms are known to possess pores, 
such extracellular substance must be in close association with 
the cytoplasm of the cell and it is not at all difficult to conceive 
of it as a part of the protoplasm. Some of the peculiar creep- 
ing movements of the diatoms and desmids are perhaps expli- 
cable upon these facts. 
2. Sexual Cell Unions and Nuclear Fusions. 
The test of a sexual act must lie with the history of the ele- 
ments which fuse. If these are shown by their morphology and 
developmental history to be sexual cells or gametes then their 
fusion becomes a sexual process. There are cell and even 
nuclear fusions which have the physiological appearances of 
sexual acts but cannot be so considered because the elements 
concerned have plainly no relation to sexual cells, which are 
