May i?E -Royal Microscoj>{eaI Society. 279 
this lifeless, passive, formed matter, which, cannot move or grow or 
multiply of itself, which is but a product of the death of protoplasm, 
is nevertheless to be called by the same name as the hving, moving 
substance which it once was ? If this be so, there ought to be no 
recognizable difference between matter which is actually alive and 
the substances which result from its death. 
So far, then, we have seen that the term protoplasm has been* 
apphed to the matter within the primordial utricle of the vegetable 
cell, to that clear substance which undergoes vacuolation and fibril- 
lation, and to the matter forming the walls of the vacuoles and the 
threads or fibrillae. Still more recently, Yon Mohl's primordial 
utricle has been called protoplasm by Professor Huxley, who some 
years before restricted the term to the matter within the primor- 
dial utricle, which matter at that time he regarded as an " accidental 
anatomical modification " of the endoplast, and of little importance.* 
The nucleus, and with it the protoplasm, Mr. Huxley thought, 
exerted no peculiar office, and possessed no metabolic power. Now, 
however, he considers " protoplasm " of the first importance ; and 
under this term includes, I imagine, not only the primordial utricle 
and the " accidental anatomical modifications " it encloses, but the 
fully-formed cellulose wall of the vegetable cell. His " endoplast " 
and "periplastic suhstance" of 1853 together constitute his "proto- 
plasm" of 1869. 
Max. Schultze included under the head of protoplasm the active 
moving matter forming the sarcode of the Ehizopods as well as the 
substance circulating in the cells of Yallisneria, the hairs of the 
nettle, and other vegetable cells ; and now it is generally admitted that 
the active, moving matter constituting the white blood-corpuscle, 
the mucus and pus corpuscle, and other contractile bodies widely 
distributed, is essentially of the same nature. The movements 
characteristic of this matter have been attributed to an inherent 
property of contractility ; and this property has been held by some 
to be characteristic of, and peculiar to, protoplasm. Kiihne considers 
all contractile material to be protoplasm, and includes the different 
forms of muscular tissue in the same category as the matter of the 
amoeba, white blood-corpuscle, &c. But if we apply the term proto- 
plasm to the contracting muscular tissue which exhibits structure^ 
as well as to the living moving matter of the amoeba, &c., in which 
no structure at all can be made out, it is obvious that these must be 
regarded as essentially different kinds of protoplasm, because they 
differ in properties which are essential and of the first importance. 
The contractile movement of the amoeba, white blood-corpuscle, &c., 
is a phenomenon very different from the contraction of muscular 
tissue. In the first, movements occur in every direction, while the 
last is characterized by a repetition of movement in two definite 
* " The Cell Theory," ' Med. Chir. Bev.,' October, 1863. 
