THE ORGANIC CELL 
88 
secondarily through adaptation of the cell to its environment 
in the tissues.’ This can be shown clearly in epithelium, which 
of the cells here differ widely in relation to the food-supply, and 
show a corresponding structural differentiation. In such cells 
the nucleus usually lies nearer the basal end, toward the source 
of food, while the differentiated products of cell-activity are 
formed either at the free end or at the basal end.’ 
These two theories widely differ, but in some cases lead 
to the same result. This is the case with the ovum and sper- 
matozoon, for in these cases the morphological and physiological 
axes are the same. This has also been shown to be the case in 
certain epithelia, the centrosomes here lying very often near 
the surface, and there is evidence to show that the basal bodies 
the centrosomes. 
The Multicellular Body and the Cell-unit 
Perhaps there is no biological problem of greater importance 
than the proper understanding of the means by which the 
individual cell -activities are co-ordinated, and the organic unity 
Vol. IV. — No. 7. b 
is the most primitive of all tissues. ‘ The free and basal ends 
C. In a 
ciliated cell. 
B. C. Phy- 
siological 
B. In a 
gland-cell. 
Rabl and 
Hatschek. 
OIU Iv/glv CAI L 
polarity of 
A 
jB 
Rabl. 
c 
Van Beneden. 
Hatschek 
to which the cilia are attached in ciliated epithelium may be 
