ACNE. — SYCOSIS. 393 



■within during pregnancy. This led me to subject bits of healthy 

 skin to a renewed examination ; and I then found that wherever 

 ii hair-sac of medium or large size (I except only the smallest 

 lanugo-hairs) was implanted in the cutis, it lay, not so much in 

 its substance, as in a sort of prolongation of the subcutaneous 

 connective tissue. Now should a follicle of this kind increase in 

 size from any cause, it must separate the fibrous bundles of the 

 corium from one another quite as effectually as dilating pressure 

 from below ; the recess is opened up ; and the above-mentioned 

 prolongation of lax connective tissue acts as a gubernaculum to 

 guide the hair-sac in its descent into the subcutaneous tissue.* 



/3. Inflammation. 



§ 335. The state of things in the interior of the hair-follicle, 

 and especially the retention of its secretion, cannot continue 

 without reacting on surrounding parts. We have seen that in 

 molluscum contagiosum, as well as in atheromatous cysts, 

 hyperplastic changes in the surrounding connective tissue were 

 excited by the retained secretions, changes wdiich ultimately 

 resulted in swelling and thickening. Inflammation of the hair- 

 gacs — or rather inflammatory processes starting from the hair-sacs 

 — proves however, that this reaction of the environment against 

 the morbid state of the follicle, may also assume an acute and 

 heteroplastic character. 



§ 336. What is known as Acne, presents us with a series of 

 anatomical phenomena, consisting essentially of retention of 

 secreted matters on the one hand, and of a perifoUicular inflam- 

 mation on the other. This eruption is very common as an 

 accidental complication of comedones and milia. It may be that 

 the products resulting from decomposition of the stagnant con- 

 tents of the follicle act as irritants upon the cutis. A more 

 luilikely supposition is that the perifollicular inflammation is 

 primary ; that it causes swelling of the subepithelial connective 

 tissue about the neck of the hair-sac ; and so, by stopping up its 

 mouth, brings about an accumulation of secreted matters as a 



* Wertheim had already pointed out (in 1864) the mode of implanta- 

 tion of the hair-sac, and shown that it passed directly into a fasciculus 

 of connective tissue coming from the deeper layers. (On the Structure 

 of the Hair- Sac in Man, &c. Sitzber. der Kais. Akad. Bd. L. April.) 



