94 VARIOUS KINDS OF PROTOPLASM. 



can only uncoil itself after it has been wound up. Hence, 

 these two kinds of moving and contracting material are very 

 different, and ought not to be called by the same name- 

 Protoplasm. 



Many different kinds of matter called ^Protoplasm" 

 Further, the term protoplasm has not been applied only 

 to the matter of which the amoeba, the sarcode of the 

 foraminifera, &c., is composed, and that which constitutes 

 the white blood-corpuscle and such bodies, but the matter 

 which is gradually acquiring the characters of tissue has 

 been considered to be of the same nature. The radiating 

 fibres of the caudate nerve-cells of the spinal cord have been 

 termed protoplasm fibres, and the outer part of the nerve- 

 cell with which they are continuous is composed of the 

 same substance. The axis-cylinder of the dark-bordered 

 nerve-fibres and the fine ultimate nerve-fibres in peripheral 

 parts have been looked upon as a form of protoplasm ; but 

 it is hardly necessary to remark that, whatever may be the 

 nature of the material of which nerve-fibres and the outer 

 parts of nerve-cells are composed, this possesses properties 

 very different from those manifested by the amoeba, white 

 blood-corpuscle, &c., while it is destitute of the powers 

 which characterise the matter constituting these bodies. 

 Here again we find the term protoplasm applied to dif- 

 ferent kinds of matter or to matter in very different states. 

 But, unfortunately we have by no means exhausted the 

 confusion which has resulted with regard to protoplasm, for 

 the name has been applied also to the outer, hard, dead 

 part of epithelial cells, and by implication to all correspond- 

 ing structures. 



The Protoplasm of Huxley the Basis of Physical Life, or 



