PART II.] Alterations of Tissues in the Delhi Sore. 425 



modified by the morbid process associated witb Delhi sore will suffice to indicate in a 

 general way the principal alterations which the tissues have undergone. The horny 

 layer of the cuticle (Fig. 22, a) is found to have become thickened, except at the 

 site of actual breach of continuity, and the mucous layer (6) has become much more 

 pronounced in its character, not only by increased thickness, but also by its more 

 cellular character. The epithelial cells have become distended and their nucleus 

 more distinct, and the epithelial character of the inter-papillary processes is much 

 more distinctly marked than is the case in sections of normal tissue. The prickly 

 appearance of a large portion of the epithelial cells is well marked. 



The papillae likewise are enlarged in all directions, and frequently their contained 

 capillaries are found much congested, rows of tightly packed red corpuscles being 

 frequently distinguishable along the entire length of a papilla. 



The most marked alteration, however, which the papillae manifest is due to the 

 number of lymphoid corpuscles which occupy every available crevice between their 

 vascular and other tissues ; but, except in case of actual rupture, as at c, these 

 corpuscular elements do not extend beyond the epithelial boundary of the papilla. 

 It is seldom that a lymphoid corpuscle can be observed entangled in the midst of the 

 cells forming the Malpighian layer, whose presence there cannot pretty clearly be 

 attributed to accidental causes in connection with the preparation of the specimen. 



On examining a vertical section of a hardened specimen of the sore under a low 

 power, by the aid of reflected light, striae of these corpuscular elements may be 

 observed descending through the corium in a direction towards the base of the tumour 

 and continuous with the lumen of the papillae. When thus examined, the striae 

 present a whitish, pearly aspect. These striae manifestly correspond to the pinkish 

 strJEe which we have just described as being conspicuous in perfectly fresh prepara- 

 tions, owing to the congested condition of the blood-vessels along which the lymphoid 

 corpuscles are in great part distributed. The colouring matter, however, of the red 

 blood cells gradually disappears in course of preservation. 



The spaces between the striae are occupied in the upper part of the section by 

 prolongations formed of epithelial cells continuous with the rete Malpighii, which 

 gradually assume a more spindle-cell aspect the further they are removed from the 

 ordinary level of the mucous layer, and in the lower part by connective tissue. 

 Where, however, the striae become less evident, and when the bands of connective 

 tissue in the corium are seen to decussate in a more marked manner (Fig. 22, 'p), the 

 pearly striae disappear and isolated aggregations of similar aspect may be seen 

 between the meshes of the fibrous tissue. The application of a higher magnifying 

 power shows that the corpuscular elements forming these pearly (when examined by 

 reflected light) areas consist of lymphoid cells identical with those which occupy the 

 papillae, and which are what may be considered as the strictly new growth in Delhi 

 sore. 



Various other changes are manifested in a preparation of the sore, which 



