Intestinal Mucous Membrane. 
1884.] 
283 
intestinal epithelia lose the power of taking up solids. In 
these protoplasm processes of differentiation must appear 
m virtue of which they appear adapted solely for taking up 
ceitain determinate matters which have undergone chemical 
modifications. In short, the simple cell now, like the cells 
of glands, displays a selective power with referenec to the 
matter to be taken up. 
. This view must be capable of experimental conrfimation 
in those vertebrates whose intestinal canal is devoid of 
complex glands, as in Amphioxus and in the Cyclostomi. 
