PRODUCTS, ADVENTITIOUS. 



134 



cortical, undergo softening and rarefaction, 

 and are gradually spread out into a globular 

 sac. New bony matter is also thrown out, help- 

 ing to complete the capsule, which is, even with 

 this assistance, commonly imperfect. When 

 developed in bones of very spongy texture, 

 perforation may, according to Miiller, occur, 

 instead of expansion ; we believe that, in at 

 least some such cases, the growth originates 

 in the sub-periosteal cellular membrane. In 

 this latter variety the form is less regularly 

 spheroidal than in the other; but the texture 

 is the same in both. 



The progress of enchondroma is slow ; its 

 effects fundamentally are purely mechanical. 

 Adhesion of the skin only occurs as an acci- 

 dental effect of inflammation : rupture of that 

 membrane only from excessive distension ^ 

 the resulting ulcer may discharge abundantly, 

 and inflammation arise from this cause, as from 

 external injuries, but not apparently from in- 

 trinsic spontaneous changes. x 



Enchondroma of the bones, like every other 

 affection of those organs attended with en- 

 largement, has been described under the 

 names osteosarcoma, osteosteatoma, and spina 

 ventosa terms devoid of definite significa- 

 tion. Scarpa speaks of it as " malignant 

 exostosis," a double misnomer for its course 

 differs essentially, as has been seen, from 

 that of cancerous maladies, and it does not 

 necessarily spring from bone. 



Colloid cancer might possibly "be confounded 

 with enchondroma. We have already alluded 

 to a rude mark of distinction between the 

 two products ; further, colloid cancer rarely 

 (never so far as our experience goes) occurs 

 in bone, the chosen site of enchondroma ; the 

 effects of the two products on adjoining 

 tissues are essentially different enchon- 

 droma never infiltrates structures, colloid fre- 

 quently does ; colloid never contains patches 

 of bone, enchondroma does so commonly:; 

 colloid is of protein basis, enchondroma yields 

 chondrin, or (rarely) glutin. 



Certain sarcomata of the maxilte have 

 much outward resemblance to enchondroma ; 

 but they contain spherical <cells with granules 

 and fusiform corpuscles, and are besides of 

 albuminous composition, 



3. OSTEOMA. 



The arrangement of abnormal ossifications 

 has puzzled more than one pathologist. 

 Excluding exostosis and hyperostosis (mere 

 local and general hypertrophies) we propose 

 to examine here all varieties of bone-produc- 

 tion in unnatural sites. We adopt this course, 

 in order to avoid recurrence to the subject un- 

 der the head of PSEUDO TISSUES, being aware 

 that ossiform masses, having the generic attri- 

 butes of Growths, ought alone to figure in the 

 present place. Hypertrophy and new produc- 

 tion of bone, as in the venereal node, are fre- 

 quently associated ; and adventitious bone 

 (whether springing from anew cartilaginous 

 matrix or not) is very rarely perfect micro- 

 scopically, perhaps never so chemically : two 

 fundamental propositions. 



Adventitious bone forms (a) as an infiltra- 

 tion of natural tissues ; (b) as the callus of 

 fractured cartilage ; (c) as an osteophyte ; (d) 

 as an ostema ; (e) as an osteoid ; (/ ) as an in- 

 filtration of new products. 



(a) In the natural tissues. Articular carti- 

 lages ossify in some situations with advance of 

 life, as for instance, in the cranium; the ma- 

 terial uniting eroded articular surfaces ossifies ; 

 ossification of the costal and laryngeal carti- 

 lages (perhaps more common in phthisis, in 

 proportion to the age at death, than in other 

 maladies) is affected by calcareous deposition 

 in the cartilage cells and inter-cell substance, 

 and by generation of new bone lacunas. Carti- 

 lage morbidly ossified, as that naturally ossi- 

 fied, yields glutin and not chondrin. The 

 anterior vertebral ligament is sometimes os- 

 sified in tubercular caries of the spine. We 

 have seen the tendons of the legs infiltrated 

 with ossiform substance. The fibrous cap- 

 sules of the spleen and kidneys are sometimes 

 thus affected, and aponeuroses and fasciae are 

 often, and the elastic ligamentum nuchae, more 

 rarely, in a similar predicament. Cellular 

 membrane. The submucous tissue of the gall- 

 bladder; the subserous of the pleura (as a 

 specimen before us proves) ; the subretinal ; 

 the mtra-muscular ; the parenchymatous (of the 

 liver) ^ are all the occasional seats of bone de- 

 velopment. Muscle has disappeared and been 

 replaced by bone in some rare cases ; the crys- 

 talline lens has been similarly destroyed. 



(b) Fractured cartilage is healed not by 

 cartilaginous, but by fibrous or osseous, sub- 

 stance. 



(c) Under the name of osteophyte (Lobstein) 

 we include ossiform products generated ex- 

 ternally to, but under the influence of, some 

 one of the natural bones. Formed from 

 extra-osseous exudation an osteophyte may be 

 separated from its parent bone, without 

 necessary injury of this (herein differing from 

 true exostosis); and is produced indepen- 

 dently of, or in connection with, other pre- 

 existing new formations. 



Osteophytes assume shapes singular and 

 various, yet in some measure characteristic of 

 their origin. Thus they are flat, and more 

 or less broad in nodes ; narrow, triangular, 

 and semicircular in cephalhaematoma ; folia- 

 ceous, (Jig. 97), stalactiform, cauliflower, 



Fig. 97. 



Foliaceous osteophyte of the clavicle; the folia (6) 

 running at right angles with the axis of tfte bont (a). 

 (V. <7. Jftts.) 



(U. C. Mus.), or stellate, when plunging into 

 soft growths ; styloid when passing in front 



