26^ The Microscope. 



siderable time towards its study, declares it still a riddle and a 

 mj'^stery. However, this is not so true with regard to its struc- 

 ture and organization, as it is with regard to its physiological 

 activity. Undoubtedly the nucleus must be considered a body 

 sui generis, as it were, a cell within a cell, and in a certain sense 

 autonomous to a cell ; nevertheless it possesses a structure pecu- 

 liar to itself and may be considered incapable of living outside 

 a cell. AVe may distinguish three elements in it : the membrane, 

 the protojilastic portion and the nuclein element. 



Structurally, mor[)hological]y and physiologically, the nuclear 

 membrane and protoplasm do not differ greatly from the cell- 

 membrane and cell-protoplasm ; but in the nucleus we find an 

 element not represented in the general cell-protoplasm, and this 

 is the nuclein tubule. This element always assumes a particular 

 form, so that the older authors spoke of it as the figured bodies 

 of the nucleus. 



Before proceeding an}'^ further it becomes necessary to decide 

 upon a terminology which we are to use. So far, no terminolo- 

 gy has been agreed upon, and in fact the one now existing is, 

 for the most part, misleading, inappropriate and even in some 

 cases nonsensical. With regard to the limiting membrane of the 

 nucleus, it will be sufficient to call it nuclear membrane or wall 

 in contradistinction to the cell-membrane or cell-wall. As al- 

 ready stated, the nucleus has also a protoplastic portion, and 

 this, although derived originally from the cell-protoplasm, and 

 having an analogous structure, nevertheless is distinct, and this 

 diflerence must be expressed by a properlj' selected term. 



In 1882 Strasburger re-introduced the term cytoplasma, which 

 is very appropriately applied to the cellular protoplasma. Flem- 

 ming also introduced the cytoplasma in 1882 to replace that 

 hybrid term nucleoplasma, composed of a Latin and a Greek 

 word. 



The term caryoplasm is appropriately chosen to represent the 

 nuclear protoplasm, but Flemming did not attach to it the same 

 meaning which Carnoy gave it in 1884. The former uses it to 

 designate the figured bodies or the nuclein ; but the latter in 

 the sense of nuclear protoplasm. Although these two terms 

 are strictly speaking not necessary, still they may be used, 

 sometimes to great advantage, one to represent the cellular pro- 

 toplasm and the other nuclear protoplasm. 



