434 SIMPLE TUMOURS. 



constituting fungus lirematcde:: : from the periosteum ; and in 

 man from the medullary tissue of bones ; and, secondarily, 

 these orxowths invade the lungs, and afterwards affect the 

 more vascular organs, in which there is a complex capillaiy 

 network. 



"When cut into, they are of a uniform soft, brain-like con- 

 sistence, of a reddish white or grey colour, somewhat translucent 

 or opaque, very vasoular, the blood-vessels being often dilated, 

 varicose, and liable to rupture, which gives rise to ecchymoses, 

 the formation of blood cysts, and, if the skin be broken, to 

 haemorrhage. On scraping the cut surface, a tliickish juice, rich 

 in cells, is obtained, and on this account, as well as their other 

 clinical characters, they have been confounded with medullary 

 cancer, from which they are distinguished by the absence of 

 alveolte and stroma, and by the uniformity of the character of 

 their cells. 



The other tumours belonging to this group, gllomcL, growing 

 from the connective tissue of the brain, spinal cord, and nerves» 

 are large round-celled sarcoma, '^hich specially affect the mucous 

 tissue of the pharynx and posterior nerves, where it forms a 

 firm, almost fibrous, pale polypoid growth. 



Spindle-celled Saronma. — In this tumour there is an attempt 

 at the formation of a higher type of connective tissue tlian in 

 the round-celled varieties. They approach tlio fibroma to some 

 extent, but are slightly mali^^nant ; the intercellular substance 

 is sometimes very scanty, or almost impercoptible, whilst iu 

 other cases it is more abiir.hint; the cells, however, are elon- 

 gated, and throw out spindles of varying length. BotJi large 

 and small spiudle-celled sarcoma rarely give rise to secondaiy 

 growths, and are genrrally surrounded by a more or less definite 

 capsule ; are firm, sAlid. or elastic, and prbsout a pole lieshy- 

 looking surface on section. 



Tltc Myeloid Sarcoma. — This is a spindlo-cellod sarcoma, 

 consisting of small spindle colls with the addition of the large 

 many nucleated cells, temied myeloid cells, and the tumour 

 generally grows in connection with bone, particulnrly w-itli tb« 

 jaws, constituting one of the terms of* what is familiarly knowu 

 as osteo-sarcoma, commonly seen in the ox. They generally cal- 

 cify, and are consiiK red tlie least malignant of all the snivomata. 



It may here be stated that, with tlie exception of the cmali 



