400 MOEBID ANATOMY OF THE SKIN. 



tion of the nodule may be due to the degeneration of some 

 pre-existing structure of the same sort — such as that of the 

 sebaceous glands — suggests itself spontaneously. Now if we 

 make vertical sections through the advancing border of the 

 lupus, sections which include both healthy skin and that which 

 is completely diseased, we see at a glance, that the sebaceous 

 glands do really take a very important part in the disease. 

 It has long been known that at the extreme periphery of 

 the aifected region they s\yell np and shine through the cuticle 

 as white nodules. This swelling is due, partly to a proliferation 

 of the glandular elements, partly to the fact, that instead of 

 undergoing fatty degeneration, the cells grow large and vesi- 

 cular, distending the body of the gland even to five times its 

 normal bulk. The root-sheath of the hair also takes part in this- 

 degenerative change by producing, instead of the usual flattened 

 epidermic cells, large vesicular corpuscles like those produced 

 by the sebaceous gland. This productive activity, however, is 

 not as a rule exhibited by the entire root-sheath in the same 

 degree; it is now confined to the fundus, now it involves the 

 fundus together with one or more points above it ; this very 

 soon gives the hair-sac proper a varicose and knotty aspect. The 

 hair perishes. Glands can no longer be distinguished from hair- 

 sacs ; they are all exactly alike. Yet up to this point the con- 

 dition is in no sense peculiar to lupus ; since the metaplastic 

 enlaro-ement of the cells is also found in the neiohbourhood of 

 leprous, syphilitic, and especially epitheliomatous diseases of the 

 skin. The characteristic part of the disorder is that which imme- 

 diately ensues. 



§ 345. Lupus has been held on various grounds to be a pro- 

 liferation of the corpuscular elements of the rete Malpighii 

 (Berger^ Dissertatio inaugur. Greifswald ; and Polilj Virclioics 

 Archiv, Bd. vi.). I may be said to agree with this view in one 

 sense, inasmuch as I too seek to localise the proliferation at the 

 junction of the epithelial and connective-tissue layers ; but I do 

 not limit it to the rete Malpighii, i.e. to the boundary-line between 

 connective tissue and ej^idermis in its stricter sense ; on the con- 

 trary, I regard it as concentrated in the glandular inflexions of 

 the epidermis. The process begins as a luxuriant corpuscular 

 proliferation in the interstitial and capsular connective tissue of 

 the sebaceous and sudoriparous glands. This proliferation extends 



