28 BOVINE PATHOLOGY. 



i£ ever, results from pus production by the serous mem- 

 brane, but from bursting of an abscess into tbe serous 

 sac. It has been observed that layers of fibrous tissue, 

 fascisB, aponeuroses, limit the extent of abscesses. A 

 knowledge of the position of these is, therefore, important 

 from a surgical aspect, for when externally placed to the 

 pus accumulation they oppose that extension of the abscess 

 towards the surface which leads to evacuation of the pus 

 by bursting through the skin. The local symptoms of for- 

 mation of an abscess are primarily hardness of the diseased 

 parts, with an oedematous condition of the tissues around, 

 with elevation of temperature, and throbbing of the arteries 

 of supply ; then the centre of the seat gradually becomes 

 softer, and at length fluctuates on pressure. The part is 

 swollen and most prominent centrally. After this the fluc- 

 tuation extends from the centre, where the hairs fall off, and 

 a slight amount of serous fluid exudes until the pressure of 

 pus in the abscess bursts the skin, which has been much 

 attenuated by absorption, and thus the pent-up fluid 

 escapes ; and any which forms after this also escapes, for 

 nature has produced an opening with a jagged edge, such 

 as does not readily close. As the pus, which is now pro- 

 duced, exerts no pressure on the abscess-walls, a rapid 

 closure of the cavity results from deposition of lymph 

 around its walls, each layer undergoing changes which 

 terminate in conversion of them, in order of seniority, into 

 an organised tissue somewhat resembling the white fibrous. 

 This process is termed granulation. By it, finally, the 

 cavity is filled ; then the external wound closes. Escape 

 of pus by bursting of an abscess on to the surface of the 

 body, or of a mucous membrane, is a very salutary process. 

 But it may take place into serous cavities and other in- 

 ternal spaces when the result is not so satisfactory. 

 Evacuation of pus from a mucous membrane is often to be 

 encouraged as being nature's method of relief of its in- 

 flamed state. When pus does not become removed by 

 natural or artificial evacuation, its permanence or the 

 reverse will depend upon the state of the vessels of the 

 parts, and also on whether its corpuscles undergo the 



