PLASM 



General Morplioloi^y: "The two functions of heredity 

 and adaptation seem to be not yet distributed between 

 differentiated substances in the unnucleated cytodes, 

 but to inhere in the whole of the homogeneous mass 

 of the plasm; while in the nucleated cell they are di- 

 vided between the two active constituents of the cell, 

 the inner nucleus taking over the transmission of hered- 

 itary characters and the outer plasm undertaking 

 adaptation, or the accommodation to the features of the 

 environment." This hypothesis was afterwards (1873) 

 confirmed by the discoveries of Strasburger, the brothers 

 Hertwig, and others, with regard to cell-cleavage and 

 fertilization ; it is particularly supported by the phenom- 

 ena of caryokinesis (the movement of the nucleus) in 

 sexual generation. Hence we can understand how it is 

 that in the monera (chromacea and bacteria), which 

 propagate by simple cleavage, there is no sexual genera- 

 tion and no nucleus. 



The great significance of the nucleus in the life of the 

 cell, as central organ of heredity, and also probably as 

 "the soul of the cell," depends chiefly on the chemical 

 properties of its albuminous matter, the caryoplasm. 

 This one indispensable nuclear element is chemically 

 akin to the cytoplasm of the cell-body, but differs from it 

 in certain respects. The caryoplasm has a greater 

 affinity for many coloring matters (carmine, haematoxy- 

 lin, etc.) than the cytoplasm; and the former coagulates 

 more quickly and firmly than the latter through acids 

 (such as acetic and chromic acid). Hence we need only 

 add a drop of diluted (two per cent.) acetic acid to cells 

 that seem homogeneous to make perfectly clear the 

 separation between the inner nucleus and outer body. 

 As a rule, the firmer nucleus then stands out sharply as a 

 globular or oval particle of plasm; occasionally it has 

 other forms (cylindrical, conical, spiral, or branched). 

 The caryoplasm seems to be originally quite homogene- 



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