THE INTERPHASE CELL AND THE CYTOPLASM 



inwards, the granules become denser and occasional vacuoles are to be 

 seen. Next to the nucleus is usually an area of darkish cytoplasm, the 

 cytocentre or centrosphere. It is free of large granules, though its 

 structure is not homogeneous; there may be some vacuoles within it. 

 The distinction between this body and the surrounding cytoplasm is a 

 variable one; sometimes there is almost a sharp boundary, in other 

 cells the whole structure can easily be overlooked. Strangeways and 

 Canti^ describe it as follows : 'The centrosphere is seen as a distinct area 

 lying as a cap over one side of the nucleus and contains a number of 

 faint granules or filaments'. 



In phase-contrast micrographs of malignant cells of a mouse sar- 

 coma, LuDFORD and Smiles^^ have shown that here also the centro- 

 sphere ranges in size and distinctness from cell to cell. It has no special 

 absorption in the ultraviolet. Generally it consists of a finely granular 

 mass, but occasionally within it these authors state that there is a 

 suggestion of a canalicular system. They are doubtful whether this 

 corresponds to the reticulate structure of impregnated preparations, 

 because such an appearance within the central body of the living cell is 

 but rarely seen. The centrosphere is clearly shown by dark-ground 

 illumination in a photomicrograph of a rat heart fibroblast published 

 by LuDFORD in 1935, who says that this body corresponds 'to the 

 Golgi apparatus of silver and osmic impregnation preparations'. A 

 continuous and lobulated body of impregnated material is seen by the 

 side of the nucleus in cells of a hepatic epithelium in culture described 

 by Richardson. I*' Similar preparations of Hill^^ of chick osteoblasts 

 show only a number of discrete impregnated granules near the nucleus, 

 arranged so as to suggest that the cytocentre includes, or is closely sur- 

 rounded by this osmophilic material.* Some recent investigations by 

 Palade and Claude^^ have still further increased the probability that 

 in the living cell the Golgi material is represented solely by globular 

 elements, a view for which Baker^^ ^^ has already assembled much 

 evidence. It appears, however, that in living cells of the pancreas, the 

 Golgi bodies are in the form of 'clear canals' (Bensley^^). 



Palade and Claude isolated cells from a number of mammalian 

 and embryonic chick tissues. They found that their lipoid inclusions, 

 unlike the mitochondria, were stable in form when the cells were 

 suspended in various media; but that when ethyl alcohol was added 

 thereto, these droplets within the cells began to swell and to form 

 myelin figures, which 'duplicate faithfully the numerous and different 

 forms ascribed at various times to the Golgi apparatus'. Experiments 

 with model substances showed that a high proportion of phospholipines 

 was necessary to give this effect. They then went on to inquire whether 



* Lasfargues and Di Fine^^ have recently shown by vital staining methods that the 

 Golgi zone in cells in tissue culture is composed of granular elements. 



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