NON-INFLAMMATORY FORMATIONS. 



331 



surface, and have not been propagated per contiguiun from neigh- 

 bouring organs) are all strikingly characterised by their very 

 superficial position. Scirrlms looks like a pasty mass "whicli 

 has been uniformly spread out over the serous surface" {Rohi- 

 tanski) ; medullary cancer resembles scirrhus, or takes the form 

 of roundish flattened protuberances ; colloid cancer occurs '- in 

 the form of nodules, which occasionally grow to an amazing 

 size, and are almost free in the serous cavity, i.e. adhere to its 

 walls by a few insignificant vascular attachments " ; the spindle- 

 cell sarcoma as a fungoid vegetation. Finally, the miliary 

 tubercle looks very like a grey, miliary A^esicle. Most of these 

 growths can readily be scraped from the serous surface with a 

 knife ; the latter is left somewhat rough, but without any im- 

 portant loss of substance. It is quite clear that the quantity 

 of connective tissue which lias been requisitioned from the 

 healthy serous membrane by the growth, is extremely small ; 

 hence it is on serous membranes that we are best able to study 



Fig. 107. 



MiUary tubercle of the omentum, -^^q, {Mch.) 



the essential texture of these growths, with least risk of being 

 misled by adventitious constituents. To what is this superficial 

 localisation due ? It is due to tlie fact that these tumours, taken 

 in the aggregate, are — at least primarily — outgrowths from 



