KINDS OF PROTOPLASM. 



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 protoplasm 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 proper- 

 ties which are essential and of the first importance. The 

 contractile movement of the amoeba, white blood-cor- 

 puscle, &c., is a phenomenon very different from the con- 

 traction of muscular tissue. In the first, movements occur 

 in every direction, while the last is characterized by a repe- 

 tition of movement in two definite directions only. And 

 when we come to study the matter which is the seat of these 

 two kinds of movements respectively, we find very im- 

 portant differences. The matter of the amoeba, \vhite 

 blood-corpuscle, &c., grows. // takes up matter unlike itself, 

 and communicates 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 direc- 

 tion, 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 



