280 
Transactions of the 
[Monthly Microscopical 
Journal, May 1, 1869- 
directions only. And when we come to study the matter which is 
the seat of these two kinds of movements respectively, we find very 
important differences. The matter of the amoeba, white blood- 
corpuscle, &c., grows. It takes ujo matter unlike itself, and com- 
municates to it its own properties. Now, muscular tissue does not 
do this. In short, the first kind of matter acts and moves of itself ; 
• but the last can only be acted upon and made to move. The first 
may be compared to a spring, as yet undiscovered, which not only 
winds itself up and uncoils, but every part of which moves in any 
direction, and can make new springs out of matter which has none 
of the properties of a spring ; the last to a spring which can only 
uncoil itself after it has been wound up. 
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 assuming the form 
of tissue has been considered to be of the same nature. The ra- 
diating 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 Ihe 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 part of nerve-cells are composed, it possesses properties very 
difi'erent to those manifested by the amoeba, white blood-corpuscle, 
&c., and is destitute of the powers which characterize the matter 
constituting these bodies. Here again we find the term protoplasm 
applied to different kinds of matter or to matter in very different 
states. 
But unfortunately we have by no means exhausted the con- 
fusion 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 corresponding structures. 
Up to this time all observers have agreed in opinion that the 
cell or elementary part of the fully-formed organism consists of 
different kinds of matter, and it has been supposed that distinct 
offices were performed by some of these. They have been variously 
named. Cell-wall, cell-contents, nucleus, nucleolus, periplast, endo- 
plast, primordial utricle, protoplasm, living matter and formed 
matter, are not all the terms that have been proposed. I think 
Prof. Huxley is the first observer* who has spoken of the cell in 
its entirety as a mass of protoplasm, and the only one who has ever 
asserted that any tissue in nature is composed throughout of matter 
which can properly be regarded as of one kind. This view appears 
* " On the Physical Basis of Life," ' Fortnightly Review,' February 1, 1869. 
