THE WONDERS OF LIFE 



name "protoplasm" in 1846, used it to designate a part 

 of the contents of the ordinary plant-cell — namely, the 

 viscous matter that Schleiden called ''cell-mucus," which 

 is found on the inner surface of the cell-wall, and often 

 forms a varying net-work or skeleton in the watery 

 fluid in the cell, and exhibits characteristic movements. 

 Mohl gave the name of "primordial skin" to this im- 

 portant wall-layer (the chief element of the plant-cell), 

 and called the material of it, as being chemically dif- 

 ferent from the other parts of the cell, protoplasm — 

 that is to say, the first (proton) or earliest formation of 

 the organism. It is important to notice that Mohl, the 

 author of the name, conceived it in a purely chemical, 

 not a morphological, sense, like Oscar Hertwig and other 

 recent cytologists. I intend to retain this early chemical 

 idea of protoplasm — or, briefly, plasm. It was also taken 

 in this sense by Max Schultze, who pointed out (in i860) 

 its extreme significance and wide distribution in all 

 living cells, and introduced an important reform of the 

 cell-theory which we will see later. 



The raixing of the chemical and the morphological 

 ideas of protoplasm has been very mischievous in recent 

 biology, and has led to great confusion. It generally 

 comes from a failure to formulate clearly the difference 

 between the two essential elements of the modern notion 

 of the cell — the anatomic distinction between the nucleus 

 and the body of the cell. The internal nucleus (or 

 car yon) had the appearance of a solid, definite, morpho- 

 logically distinct constituent of the cell; the outer and 

 softer mass which we now call the cell-body {cellctis or 

 cytosoma) seemed to be a formless and only chemically 

 definable protoplasm. It was only discovered at a later 

 date that the chemical composition of the nucleus is 

 closely akin to that of the cell-body, and that we may 

 properly associate the caryoplasm of the one with the 

 cytoplasm of the other under the general heading of 



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