PROTOPLASM. 



PROTOPLASM. 



The term "Protoplasm" is now applied to several dif- 

 ferent kinds of matter, to substances differing from one 

 another in the most essential particulars. It seems, there- 

 fore, very desirable that its meaning should be accurately 

 denned by those who employ it, or that it should be super- 

 seded by other words. If certain authorities were asked 

 to define exactly the characters of the matter which they 

 called protoplasm, we should have from those authors defi- 

 nitions applying to things essentially different from one 

 another. Hard and soft, solid and liquid, coloured and 

 colourless, opaque and transparent, granular and destitute 

 of granules, structureless and having structure, moving and 

 incapable of movement, active and passive, contractile and 

 non-contractile, growing and incapable of growth, changing 

 and incapable of change, animate and inanimate, alive and 

 dead, are some of the opposite qualities possessed by 

 different kinds of matter which have nevertheless been 

 called protoplasm. 



A definition of protoplasm, most probably written by 

 the late Professor Henfrey in " Griffith and Henfrey's 

 Micrographic Dictionary," is as follows : " Protoplasm. 

 The name applied by Mohl to the colourless or yellowish, 

 smooth or granular viscid substance, of nitrogenous con- 

 stitution, which constitutes the formative substance in the 

 contents of vegetable cells, in the condition of gelatinous 

 strata, reticulated threads and nuclear aggregations, &c. 

 It is the same substance as that formerly termed by the 



