384 MORBID ANATOMY OF THE SKIN. 



diate result of this isolation — sc. their atrophy and death. The 

 focus of softening then gives way, and liberates its contents : a 

 circumscribed loss of substance being left. Its floor and ^Yalls 

 are infiltrated to the extent of a line and more with young cells ; 

 this gives a dash of Avhite to their colour, and makes them tough 

 and bacony. A thin fluid containing a few cells and some fatty 

 debris, exudes from the raw surface ; the adjacent bundles of 

 connective tissue are slowly dissolved, and the ulcer continues to 

 increase in size until its further progress is arrested by vigorous 

 anti-syphilitic treatment. Then, and not before, a permanent 

 layer of embryonic tissue is formed upon the floor of the ulcer ; 

 it is then, and not before, that the formation of a scar begins. 

 Syphilitic scars have a strong tendency to contract. Causing 

 the utmost distortion of neighbouring parts, they shrink them- 

 selves to a mere nothing, so that after the lapse of a certain 

 time it is often impossible to infer the previous existence of a 

 syphilitic ulcer from the presence of a scar. This peculiarity too, 

 has not been explained as yet by the results of microscopic in- 

 vestigation. A syphilitic scar resembles all other scars both in 

 its structure and development. The blood-vessels are invariably 

 obliterated ; in injected specimens the syphilitic scar looks like 

 a gap in the vascular network of the skin ; whether the power- 

 ful contraction of the connective tissue may not be the cause 

 of this total obliteration of tlie vessels, must remain an open 

 question. 



So much for the development of a single syphilitic tubercle 

 in the skin. The growth and decay of many such aggregated 

 nodules lies at the root of syphilitic lupus. The nodules are now 

 small and superficial, now deeply seated and large. In the 

 former case they are usually grouped concentrically round the 

 point which was first affected; discoidal ulcers result which 

 become annular by healing from the centre, where a cicatrix is- 

 formed {Lupus syphiliticus serpiginosus). In the latter case the 

 ulcers grow deeper, they extend into the areolar tissue (Lujms 

 syph. exulcercms). There is also a hypertrophic variety of syphi- 

 litic lupus, in which isolated nodules of relatively small size are 

 developed in an abundant matrix of newly-formed connective 

 tissue. 



§ 325. The pathological anatomy of Leprosy was shrouded in 

 darkness till a very recent period. It was in 1848 that Danielssen 



