772 DISEASES OF THE WITHEES. 



The presence of one of these canals at the bottom of a wound 

 may sometimes he detected by the appearance of large, fleshy, 

 cone-shaped granulations, of a pm-phsh color, from which an ooz- 

 ing of pus takes place upon the application of pressure. 



But in another case, the orifice of the fistula may be directly 

 on the skin, surrounded with granvdations, protruding, soft and 

 bleeding upon the shghtest touch, with an escape of sanious pus 

 between them ; these granulations at a later period, flattening, as 

 the wound contracts, until the thinned skin seems to be continu- 

 ous with the smooth, reddish membrane which lines the internal 

 face of the tract. It may even happen that a process of cicatriza- 

 tion taking place around the opening will transform its external 

 outlet into a narrow strait which opens in the bottom of a cavity 

 formed by the skin drawn inwardly by the cicatricial retraction of 

 the indurated peri-fistulous tissue. 



The direct exploration of the fistula is the best mode of ascer- 

 taining its existence, direction, extent and depth, and also the 

 lesion which gives rise to it. This exploration ought to be made 

 by the taxis, since it is obvious that no instrument can communi- 

 cate an impression such as can be obtained by the touch of the 

 finger. By the hand, therefore, must be ascertained the course 

 and sinuosities of the fistula, its diverticulum, the nature of the 

 necrosed tissue, and the extent of the mortification. But this 

 manual exploration is not always possible, either because of the 

 deficient caliber of the passage, or of its sinuosity, or its length. 

 Kesort must be had to the various probes and directors in use. 



When the necrosis occupies the apex of one or more of the 

 spinous processes, and the fistvila is superficial, a slight incision 

 will expose the diseased spot to ocular inspection, and the condi- 

 tion of things may be at once fully reahzed. When the lesion is 

 limited to the cervical ligament, the eschar or slough will have 

 an olive-greenish color, and will be of soft, pultaceous consistency, 

 with a pecvdiar foetid odor, from its maceration in the pus. If 

 the necrosis has attacked the cartilages of the vertebrse, the morti- 

 fied part assumes a yellow color, with a tint of pale green. In 

 all cases, however, it is more or less loosened at its borders, and 

 diflers materially from that of the healthy tissue. And while at 

 the point of separation it is covered with a layer of granulations, 

 highly vascular, yet the continuity of the fibres between the 

 healthy and the diseased tissues still exists in the parts which are 



