PART II.] Aggregations or Colonies of Lymphoid Cells. 427 



In endeavouring to trace a connection between the lymphoid cells and the various 

 tissues of the corium, all preparations demonstrate more or less clearly that the 

 distribution of these elements is more intimately connected with the delicate fibrous 

 tissue-investment of the glandular and vascular structures than with any other tissue. 

 In following the course of a blood-vessel, for example, it will be observed that aggre- 

 gations — colonies of lymphoid cells — have formed in numerous places, and that from 

 these " colonies " ragged processes of delicate fibrous tissue may be recognised which 

 become joined to similar processes in other parts of the preparation (Fig. 22, h,h,h). 

 In other instances these delicate fibrous shreds may be seen to be directly continuous 

 with the adventitia of a vessel, and to become more and more distinctly dotted with 

 lymphoid cells until they are lost in a sheet, so to speak, of similar fibrous tissue at 

 a distant part of the preparation. Similar accumulations of these granular corpuscles 

 may also be found surrounding the blood-vessels when the latter are cut transversely 

 (Fig. 22, I), as also surrounding the convolutions of the sweat glands in connection, 

 probably, with the adventitia of their vascular tissues. 



The circumstance that the lymphatic vessels may sometimes be seen in the corium 

 to take a course some distance removed from the blood-vessels enables us also to observe 

 that in very early stages of the disease the lymphoid cells, of which we have been 

 speaking, are in more manifest relation to the connective tissue along the course of 

 the lymphatics than elsewhere ; but we have not been able to satisfy ourselves that the 

 cells are found within the larger lymphatic vessels ; on the contrary, not unfrequently 

 they form larger aggregations in the fibrous tissue which is seen to proceed from such 

 a vessel and at some distance from it. 



In addition to these aggregations or colonies of lymphoid cells which surround the 

 sweat glands, the hair and sebaceous follicles, and the different vascular tissues with 

 distinct walls, aggregations may frequently be observed without perceptible connection 

 with any of these structures (Fig. 22, k). It is possible that these colonies may be due to 

 the accumulation of the cells in the interstices formed by decussating fibrous bands, or to 

 their accumulation in the spaces of the adventitia* Possibly both conjectures are 

 correct, seeing that the outline of the colony frequently corresponds to the margins of 

 the spaces formed by the decussating fibres, and that when no such bands are present 

 to modify the shape of the colonies, they are usually round or oval. The average dimen- 

 sions of ten of the colonies which we. measured was Yhj" (=0-25 mm.), but they varied 

 from T^" (= 0-15 mm.) to ^V (=^ 0'4 mm.). 



Sometimes, as already mentioned in describing the microscopic appearances of an 

 extirpated sore (page 425), its base is dotted with minute projections about the size of 

 the head of a pin, which become more evident after the preparation has been dried or 

 hardened in spirit. These little prominences are found to consist in some cases of the 



* We have refrained from giving any name to these spaces so as to avoid the possibility of miscon- 

 struction, seeing that different writers make use of the same designations for very different structures in 

 accordance with the particular view adopted. 



