PROPERTIES OF PROTOPLASM 3 
growth and reproduction. In addition, protoplasm pos- 
sesses in great degree the power of movement as well as 
of perception. Motion is not always evident but in cer- 
tain stages at least it can almost always be found. The 
protoplasm may move as a whole or certain portions of 
the cytoplasm may stream to and fro in a most compli- 
cated manner. Such streaming may affect only the small 
granules, or the larger bodies such as nucleus and plastids 
may be transported from one place to another. 
5. Protoplasm possesses the power of imbibition of 
water. It may imbibe so much water that it becomes 
very thin and watery and yet still retain its powers of 
motion and of reproduction. ‘There is a limit, however, 
to the amount of water protoplasm will imbibe, for some 
of the naked masses of protoplasm set free by some 
plants for reproductive purposes retain their shape and 
size in spite of being immersed in water. 
6. The complex chemical and physical structure of 
protoplasm renders it very susceptible to injury. This 
injury may be simply physical, or certain of the groups 
of atoms making up the complex protoplasmic molecule 
may be changed chemically in such a way that the proper 
functions can not be carried on. When the changes reach 
such a point that on removal of these external unfavorable 
conditions the protoplasm does not resume its functions, 
we say that death has occurred. Heat, cold, electricity, 
even light, also mechanical injury such as crushing, as 
well as innumerable chemicals will cause death. Many 
of these agents when applied in smaller amounts or to . 
a lesser degree check the functions of protoplasm only 
temporarily. Thus a jar or sudden cooling will check 
for a time the streaming within the protoplasm. 
7. All of the modifications of protoplasm are, at least 
when active, in a more or less liquid state. The two 
