The Microscope. 263 



At present, the term caryoplasm, or according to others, nucle- 

 oplasm, retains no longer its original meaning. In fact, accord- 

 ing to Strasburger, caryoplasm is simply the plasma of the 

 nucleus, i. <?,, the tubule of Carno}^ which Strasburger considers 

 to be filled with nucleo-microsomata. According to Strasburger, 

 therefore, the nucleus would be simpl}^ a convolute plasmatic 

 tubule filled with microsomata and surrounded by a membrane, 

 but according to Carnoy the nucleus is composed of a surround- 

 ing membrane and a true nuclear protoplasm with its own struc- 

 ture, in which is found a convolute nuclear tubule containing 

 a substance greatly stained by methyl green, and called nuclein. 

 Caryoplasm is therefore true nuclear protoplasm, just as cyto- 

 plasm is true cellular protoplasm. 



Caryoplasm, like cytoplasm, is a hyaline and apparently homo- 

 geneous substance filled with scattered granules ; but by examin- 

 ing it more attentively under the microscope, it may be seen to 

 consist of a reticulum and a granular enchylema similar to those 

 structures found in the cytoplasm. 



The Nuclein, — This element is found under various shapes and 

 forms. The typical form, however, seems to be that of a con- 

 tinuous and convoluted tubule, wound up somewhat like a ball of 

 yarn ; and in this tubule is contained the nuclein proper. As 

 the tubule is convoluted, and therefore crosses itself over and 

 over, in these places it often unites and has the appearance of 

 a real network. The manner in which the tubule is disposed in 

 the nucleus varies greatly. Sometimes the coils or convolutions 

 are chaotic, not unfrequently they are more or less parallel and 

 cross each other at the polar ends, somewhat like longitudinal 

 lines on a terrestrial globe ; examples of this kind may be seen in 

 the testicular cells of spiders. When such cells are seen from 

 the polar ends, the tubule appears to be arranged in a radiat- 

 ing manner, but if the focusing is continued downwards, the 

 nuclein appears to be arranged in a circle, and finally the radiate 

 arrangement reappears when the opposite pole comes into focus. 

 There can hardly be any doubt as to the continuity of the 

 nuclein tubule, yet this is not always the case ; in fact, previous 

 to caryodieresis, the nuclein tubule always breaks up more or 

 less into shorter or longer pieces. 



The reason that for a long time the nuclein was believed to 

 exist in separate pieces, scattered more or less within the nucleus. 



