222 LEECHES 



that we are indebted for the more careful description of the 

 morbid changes. 



§ 174. Morbid anatomy. ^ 



As a rule the lesions are near the r 1&^** 



surface. Where the diseased 

 portion has become well devel- 

 oped there is usually a more or 

 less complete detachment of the 

 central inflammatory growth from 

 the surrounding tissue. This v^o. a<^. A piece cut from the 

 nodular or ' 'kunkur' ' growth ma}- Up ofati affected horse, showing 

 vary in its density according to several diseased foci. (Some- 



,1 . r -i. ' J 1 i what reduced.) (Fish.) 



the stage of its development. ' ^ 



During the earlier stages it is soft and easily cut ; later it be- 

 comes firmer and ultimately assumes a hard or "gritty" 

 character. 



In cutting sections it is generally the exception to cut 

 through the nodule or kunkur evenly and to have it retain its 

 proper relation with the other parts. Even if successful in 

 cutting, the nodule drops out during some of the later proces- 

 ses. In the specimens examined the lesions were confined 

 entireh' to the skin and subcutaneous tissue ; no traces of 

 muscular or glandular structure were observed. iVround the 

 central portion of the inflammatory growth there is a zone of 

 leucocytes of the mononuclear and polynuclear varieties, the 

 latter predominating. They are embedded in an abundant 

 stroma of connective tissue which is in a greater or less stage 

 of degeneration. The central portion of the zone is in some 

 cases very closely packed with the leucocytes, while toward 

 the periphery the}' are more loosely arranged and cause a 

 marked irregularity of the margin from their uneven drifting 

 into the tissue beyond. There is geueralh^ one and perhaps 

 more points where this infiltration occurs quite extensively. 

 In some of the preparations the wandering cells have been 

 traced as far as the surface of the epidermis. 



Occasionally there may be found a narrow area at the per- 

 iphery of the nodule, as seen in cross section, which is lighter in 



