ENCHONDROMATA. 173 



granule-cells, &c., these changes being farther complicated bv a 

 mucoid softening and solution of the matrix ; the final result of 

 the process being the formation of cavities, fluctuating points — in 

 a word, of " cysts due to softening " — in the interior of the 

 enchondroma, which are filled with a jelly-like viscid fluid con- 

 taining a very large proportion of mucin. This cystoid degenera- 

 tion of enchondromata {encliondroma ci/stmmi) ought certainly to 

 be regarded as a consequence of impaired nutrition. 



§ 138. Unfortunately however, this is not the last of the 

 anatomical modifications of enchondroma. The complication of 

 enchondroma with alveolar sarcoma (vulgarly called cancer on 

 account of its alveolar structure) has yet to be considered. It is 

 to this complication that enchondroma owes a certain reputation 

 for malignity, a reputation which the growth ]Der se does not 

 deserve. Cases are on record of medullary tumours appearing 

 at the seat of operation and in other regions of the body after 

 the removal of enchondromata ; such cases all refer to this com- 

 bination of enchondroma with soft sarcoma. In such cases too, 

 the superadded element of malignity can usually be recognised 

 even iu the primary tumour. Medullary nodules of variable size 

 are met with along the vessels in the stroma of the cartilaginous 

 tumour. Still, it is an established fact that pure enchon- 

 dromata are also liable to recur; a gradual extension of the 

 growth along the lymphatics, metastases to the nearest lymphatic 

 glands, nay, even to internal organs, have more than once been 

 observed. Amono^ internal viscera the lunir is the favourite 

 locality for secondary deposits of an enchondromatous nature. 

 It must be remembered, however, that these secondary deposits 

 are excessively rare, and always of extremely small size, even 

 when the dimensions of the primary tumour were colossal. 



§ 139. From a quarter to four-fifths of all enchondromata 

 occur in the osseous system, and more particularly in the 

 diaphyses of the long (tubular) bones. We shall hereafter 

 become acquainted with the great variety exhibited by enchon- 

 dromatous tumours of bone, both in the manner of their first 

 appearance, and in their subsequent development ; here I will 

 only allude to a single variety, the osteoid-cliondroma of Virchow^ 

 inasmuch as it familiarises us with an essentially aberrant form 

 of cartilage as its main constituent. In reckoning up the various 

 kinds of cartilage, one tissue is usually omitted, which neverthe- 



