196 CHAPTER 20. 



lotion. For the treatment of a sinus the reader is referred to the latter 

 part of this Chapter. 



398. Various kinds of Abscesses. 



Abscesses may be divided into acute, chronic, and specific. 



The acute abscess may be taken as a type of the disease under ordinary 

 circumstances. Though often attended with pain and fever, it generally 

 runs its course quickly, and therefore seldom needs any assistance to 

 bring it to a head. Chronic abscesses are those which slowly appear, 

 without any constitutional disturbance except swelling. The cause of 

 their appearance is often not very apparent. They frequently require to 

 be stimulated by a blister in order to hasten on the needful processes. 

 Specific abscesses are those which result directly from some disease, such 

 as strangles. 



Abscesses are frequently a result of diffuse and violent inflammation in 

 a part. They also occasionally occur as a consequence of phlebitis or 

 pyaemia. They may occur in various parts of the body, and especially in 

 the mesentery after an attack of strangles, when the tumour has not 

 formed in the regular manner. 



399. Sinus. 



A sinus is a hollow passage lined by a dense fibrous membrane, and 

 usually communicating with a suppurating cavity. This passage always 

 opens at one end on the skin or on some free surface, whilst the other 

 end is at the seat of irritation. The sinus therefore is not the disease 

 itself, but only the tube leading from the diseased part to the external 

 surface. Hence applications to a sinus are of no use unless they reach 

 the bottom of the passage, i. e. to the seat of the disease. 



When healthy action has set in at the seat of the disease, it often 

 happens notwithstanding, that the lining membrane of the sinus con- 

 tinues to pour out an exudation. In such cases the only plan is to cut 

 through its walls and to make a complete division. The surfaces must 

 then be prevented from healing too quickly by inserting a pledget of tow 

 between them. An ordinary incised wound will thus have been produced, 

 and nature will then probably heal up the parts by granulation. In 

 minor cases it may be sufficient to inject the sinus with a stimulating or 

 caustic lotion. 



400. Serous Abscesses. 



What is commonly called a Serous abscess is not in reality an abscess, 

 but merely an effusion of serum into the cellular tissue. A true abscess 

 must contain pus. Iodine ointment may be applied, and iodide of potas- 

 sium may be given internally with a view of promoting absorption. 

 These means often fail. The surest remedy is to freely open the abscess 

 with the knife, taking care to establish a dependent orifice. The wound 

 so caused needs only to be treated as an ordinary incised wound. See 

 par. 754. 



