434 SIMPLE TUMOURS. 



constituting fungus hsematodes ; from the periosteum ; and in 

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

 these growths invade the lungs, and afterwards affect the 

 more vascular organs, in which there is a complex capillary 

 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 vascular, 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 thickish 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 

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

 their cells. 



The other tumours belonging to tliis group, glioma, growing 

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

 are large round-celled sarcoma, which specially affect the mucous 

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

 firm, almost fibrous, pale polypoid growth. 



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

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

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

 extent, but are slightly malignant ; the intercellular substance 

 is sometimes very scanty, or almost imperceptible, whilst in 

 other cases it is more abundant; the cells, however, are elon- 

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

 and small spindle-celled sarcoma rarely give rise to secondary 

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

 capsule; are firm, solid, or elastic, and present a pale fleshy- 

 looking surface on section. 



The Myeloid Sarcoma. — This is a spindle-celled sarcoma, 

 consisting of small spindle cells with the addition of the large 

 many nucleated cells, termed myeloid cells, and the tumour 

 generally grows in connection with bone, particularly with the 

 jaws, constituting one of the terms of what is familiarly known 

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

 cify, and are considered the least malignant of all the sarcomata. 



It may here be stated that, with the exception of the small 



