PRODUCTS, ADVENTITIOUS. 



135 



of a vertebra destroyed by caries ; sacciform, 

 when investing a soft growth from bone ; 

 warty, when found about gouty joints ; mem- 

 braniform and lace-like in the cranium of 

 pregnant women. 



The flat osteophyte (sometimes separable 

 from the subjacent bone) is best exemplified 

 in nodes, though it forms under the influence 

 of common periostitis or adjoining inflam- 

 mation, as beautifully shown by the ribs of an 

 old sufferer from empyema, preserved in the 

 University College Museum. If a node be 

 carefully examined, it will be found in part to 

 consist of hypertrophy with rarefaction of the 

 superficial stratum of the original bone ; and 

 in part of ossified subperiosteal exudation. 

 The canaliculi in the latter run at right 

 angles with the axis of the bone, proving 

 absolutely the existence of a separate centre 

 of ossification : the fact is exemplified on a 

 large scale, in^g. 97. And it is further illus- 

 trated by a portion of carious lower jaw-bone 

 (now before us), separated from the face of a 

 dipper of Congreve matches, labouring under 

 the singular disease peculiar to workers with 

 phosphorus. On the inner surface of the 

 rarnus of the bone (kindly lent to us by Mr. 

 Quain, whose patient the man was *,) appears 

 a flattish osteophyte, partly fibrillar, partly 

 porous and pumice-stone like, of dark -greyish 

 colour, and easily separable at the edge from 

 the maxillary surface ; elsewhere are friable 

 earthy-looking particles. 



But the most singular of osteophytic pro- 

 ductions is certainly that which forms in 

 membraniform patches between the cranium 

 and dura-mater of a certain (as yet unsettled) 

 proportion of pregnant women. The natural 

 history of this production (of which a beauti- 

 ful specimen lies before us) has been unravelled 

 with great sagacity by M. Ducrest.f Exuda- 

 tion matter soft, pulpy, and reddish, forms the 

 matrix of the future osteophyte ; it soon 

 becomes sandy to the feel -, subsequently hard 

 particles of some size are felt, and these form 

 eventually one, more or less perfectly, contin- 

 uous plate. The frontal regions are its 

 chosen seat, and M. Ducrest shows that its 

 formation occurs symmetrically. Its thick- 

 ness does not exceed a sixth of an inch, and is 

 generally much less j the specimen before us 

 (irregular thickness from point to point gives 

 this a lace-like appearance) forms a coating 

 for the entire base and upper arch of the 

 skull ; but its superfical extent is very rarely so 

 considerable. When fresh it is of red colour ; 

 twice (in jaundiced women) M. Ducrest found 

 it yellow. This production, which entails 

 no symptoms, is more prone to appear in 

 young than in more aged women. 



(rf) Osteoma. By osteoma we understand 

 a growth composed of bone, and either (a) 

 altogether free from, or (b) having but very 

 slight, connection with any part of the skele- 



* This man is now in excellent health, and ma- 

 nages to masticate with the aid of a fibrous represent- 

 ative of his lost jaw. 



t Me'moires de la Soc. Me'd. d'Observation de 

 Paris, t. ii. 



ton. Tumours of the former kind (a) are of 

 excessive rarity, and are perhaps only met 

 with as results of bony infiltration of a pre- 

 existing plastic mass, either of the serous 

 cavities or of the parenchymata ; it seems un- 

 necessary to insist upon the greater frequency 

 of calcification than of true ossification of such 

 masses. Tumours of the latter kind (b) are 

 best exemplified by growths from bone, gene- 

 rally termed pedunculated exostoses, in 

 which the peduncle may be so small, and the 

 body of the growth comparatively so large, 

 that a centre of ossification distinct from the 

 original bone appears to exist. Such produc- 

 tions are not very unfrequent about the pha- 

 langes of the toes ; their texture is generally 

 loose, but may be eburniform from density. 



(f) Osteoid. Under the names of osteoid 

 or ossifying fungous tumour, Muller de- 

 scribes a growth of slow or rapid course, 

 generally springing from the surface of bones, 

 sometimes acquiring great bulk, composed of 

 porous or close osseous texture, and of a 

 greyish white, vascular, nodulated substance, 

 of the consistence of fibro-cartilage, the 

 latter lying in the interstices of the former. 

 The softer substance famishes neither glutin 

 nor chondrin by boiling, and exhibits a dense 

 fibrous rete under the microscope, containing 

 a few nucleated cells in its meshes. The for- 

 mation of osteoid growths seems dependent 

 on a peculiar diathesis ; they generally appear 

 at first on one bone, but may eventually in- 

 vade several bones and certain soft parts 

 the lungs, great vessels, &c. The removal of a 

 primary growth by amputation does not pre- 

 vent the development of others internally. 

 Cruveilhier's osteoehondrophyte (Anat. Path. 

 livrais. 34), is a production of this class ; this 

 writer calls the soft part of the tumour carti- 

 lage, but gives no proof of its being so. 



(/) Bone formation in the interior of new 

 products (exclusive of osteophytes springing 

 from some part of the skeleton) is very rare. 

 We have never seen such bone in cancer or 

 in fibroma ; but there is sufficient evidence 

 that it has, in some rare instances, been ob- 

 served. 



OF UNDETERMINED BASIS. 

 COLLOMA. 



Perhaps the word Colloma will not be 

 objected to as a pro tempore name for the 

 gelatinous-looking matter, which is of common 

 occurrence in the interior of cysts, and occurs 

 less frequently, unprotected by such invest- 

 ment, in the limbs and elsewhere. Tremulous 

 and soft, sometimes sufficiently so to be almost 

 poured from the part containing it ; generally 

 amorphous, sometimes fibrillar, never stromal y 

 as seen with the naked eye, this substance 

 appears transparent and amorphous under 

 the microscope. It contains no interstitial 

 vessels. 



This substance yields no gelatin by boil- 

 ing ; nor is it composed of albumen (though 

 it may furnish traces of this principle) : it is 

 therefore chemically different from the jelly- 



K 4 



