126 THE CELL DOCTRINE. 



spontaneous movements of nucleoli by Auerbaeh, 

 Brandt, Eimer, Kidd, and others, he regards as quite 

 compatible with the above view, for Van Beneden 

 has observed movements in the intranuclear network, 

 and it is quite possible that the above assertions 

 might refer to such movements. 



With regard to the nuclear membrane already men- 

 tioned, Klein says that it is composed of an outer 

 thicker portion, which is the limiting membrane proper 

 and closely connected with it, an inner, more or less 

 incomplete layer, which is a peripheral condensation 

 of the intranuclear network, with which it is connected 

 by longer or shorter threads. The clear space some- 

 times observed between the membrane of the nucleus 

 and the intranuclear network is due to a retraction 

 of the latter from the former. 



Klein has also demonstrated a network of fibrils 

 in the substance of cells outside of the nucleus, which 

 he designates as the intracellular network, in contra- 

 distinction to intranuclear, in the meshes of which 

 again is the interfibrillar or ground^substance, which 

 in the case of the columnar epithelial cells on mucus- 

 surfaces, known as goblet-cells, is mucus,* but finds 

 them also in the endothelium of the surface, in un- 

 striped muscle-fibres, connective tissue corpuscles, and 

 nerve-fibres. 



Klein further traces a direct connection of the fibrils 



* They are best seen on the slender goblet-cells of the stomach 

 of the newt, kept for twenty-four hours in MuUer's fluid, placed 

 then for half an hour in a mixture of two parts chromic acid (J 

 per cent.), and one part methylated alcohol, washed after this in 

 water, and stained with picro-carmine. 



