DISEASES OF THE WITHERS. 773 



deeper and more central, where the connection is maintained by a 

 sort of peduncle of varying size, through which the necrosis con- 

 tinues to be propagated. If the disease is of sufficiently long 

 standing the necrosis may involve the entire thickness of the carti- 

 lage. In this case the spongy tissue of the vertebrae is exposed, 

 covered with the healthy granulations, which contribute to the cic- 

 atrization. This, however, is a rare termination, the bone, ordi- 

 narily, becoming necrosed or carious, the necrosis being indicated 

 by its brownish color, its dryness, its roughness and its sonority 

 on percussion, while the caries is recognized by its friability, its 

 red and yellowish color, the foetid suppuration which oozes from 

 its areola and the facility with which it yields to the edge of a 

 sharp cutting instrument. 



This condition of mortification may affect but a single verte- 

 bra, but it is not uncommon to find several, or possibly aU, the 

 spinous processes of the region affected. 



While the fistula may be considered as the essential physical 

 symptom of this ailment there are other symptoms coexisting. 

 There is accompanying it an external swelling, sometimes diffuse, 

 sometimes compact, and more or less indurated, according to the 

 duration of its existence ; very painful on pressure, and of which 

 the form, direction and extent so perfectly correspond with those 

 of the fistula, that it may be viewed as accurately representing 

 the extent and limits of the lesion itself. 



This induration increases in consistency, and may with time 

 become infiltrated with calcareous deposits, or even bony growths, 

 attached to the spinous processes. 



The diagnostic and prognostical importance of this induration 

 is very great. So long as there is no perceptible decrease in its 

 dimensions, no apparent improvement in the external wound or 

 modification in the nature and amount of the discharge can be of 

 any favorable signification, and the surgeon may feel thoroughly 

 assiu'ed that the disease continues unchanged in extent and char- 

 acter. As it diminishes it indicates that the necrosis is also con- 

 tracting its limits, and it becomes certain that the sloughing has 

 taken place and the wound is once again assuming its character 

 of original simplicity. And when the swelling disappears, and 

 ■ the tissues have resumed their normal integrity, questions as to 

 the depth of the fistula, or the extent of its sinuosities, and abun- 

 dance of the discharge will cease to be of any significance. 



