LESIONS IN LEPROSY. 253 



comparatively large size, and may show vacuolation of their 

 protoplasm and a vesicular type of nucleus. These are 

 often known as " lepra cells." Amongst the cellular elements 

 there is a varying amount of stroma, which in the earlier 

 lesions is scanty and delicate, but in the old lesions may 

 become very dense. Periarteritis is a common feature, and 

 very frequently the superficial nerves become involved in 

 the nodules and undergo atrophy. The tissue in the lep- 

 rous lesions is comparatively vascular, at least when young, 

 and, unlike tubercular lesions, never shows caseation. Some 

 of the lepra cells may contain several nuclei, but we do not 

 meet with cells resembling in their appearance tubercle 

 giant cells, nor does an arrangement like that in tubercle 

 follicles occur. 



In the anesthetic form the lesion of the nerves is the 

 outstanding feature. These are the seat of diffuse infiltra- 

 tions which lead to the destruction of the nerve fibres. In 

 the earlier stages, in which the chief symptoms are pains 

 along the nerves, there occur patches on the skin, often of 

 considerable size, the margin of which shows a somewhat 

 livid congestion. Later, these patches become pale in the 

 central parts, and the periphery becomes pigmented. There 

 then follow remarkable series of trophic disturbances in 

 which the skin, muscles, and bones are especially involved. 

 The skin often becomes atrophied, parchment-like, and 

 anaesthetic, and frequently is the seat of trophic changes, 

 such as the formation of pemphigoid bullae. The bones 

 become atrophied, and, owing to the irregular affection of 

 the muscles, great distortion of the extremities may result. 

 Partly owing to injury to which the feet and arms are 

 liable from their anaesthetic condition, and partly owing 

 to trophic disturbances, necrosis and separation of parts 

 are liable to occur. In this way great distortion results. 

 The lesions in the nerves are of the same nature as 

 those described above, that is, they are the result of a 

 chronic inflammatory process, but the granulation tissue 

 produced is less in amount, and has a greater tendency to 

 undergo cicatricial contraction. This is to be associated 



