GOLGI APPARATUS 5 



end of the cell to the other. It may be too bold, although fasci- 

 nating, to assume that this reversal is associated with redirection 

 of the secretion. Furthermore there is often a topographical 

 relationship between the Golgi system and the centrosome ; 

 certainly this is so in the thyroid. Here the centrosome usually 

 lies with the Golgi apparatus between the nucleus and the lumen, 

 but in some malignant tumours of this organ both structures lie 

 between the nucleus and the vascular network. It is striking that, 

 when this reversal of position has occurred in practically all the 

 cells, the acini are devoid of colloid contents. Again the sugges- 

 tion seems to be that secretion has occurred towards the Golgi 

 system, that is away from the glandular lumen, into the blood- 

 stream. 



There is still much uncertainty as to the relationship of the 

 Golgi system to the system of canals (trophospongium) described 

 by Holmgren. In many nerve cells there is no doubt that the 

 two structures are totally distinct. 



This brief introduction to the subject of cell-organs can well be 

 followed by a detailed description giving an account of recent 

 advances in histology, for that is indeed what our subject might 

 well have been termed. 



