A CLINICAL STUDY ON HYDRO A. 19
crowned by a vesicle filled with yellowish transparent fluid, which quickly dries up in the centre into a blackish crust, leaving a whitish projecting bordering (caused by softened epidermis), from which the fluid is absorbed in a few days. Sometimes the progress is rather diff'erent, and a second phase, as he supposes, is seen. It consists in a rounded transparent vesicle, surrounded by a red areola, which extends peripherally and becomes vesicular as it goes, and then dies away in the manner before described. Each element of the eruption exists four or five days, and leaves behind it a violet stain. On the second and third day, in both cases, also there may be a sore throat, usually an eruption of vesicles on the lower lip and buccal mucous membrane ; rarely also they appear on the uvula and conjunctiva. The spots are sometimes grouped, and they arise in successive crops, so that the duration of the disease may be from two to four weeks. There is also a tendency to relapses. It occurs in adults from 20 to 30 years of age, who are markedly "arthritic subjects," and rather more frequently in males than females. Spring and autumn are the seasons when it appears, and variations of tem- perature influence its occurrence. Bazin appends three illustrative cases, and distinguishes it from erythema papulatum by the fact that, though in the latter disease the papules are seen occasionally surmounted by a vesicle, it is a mere accessory condition, and there is never the peculiar evolution seen in hydroa vesiculeux ; from herpes it is separated by the peculiar grouping on an inflamed base in the former.
There are, therefore, in Bazin's account two distinct phases of eruption, and any one who reads their description and the illustra- tive cases attentively will see at once that Bazin is unwittingly de- scribing over again, in regard to one phase of this eruption, the her- pes iris of Bateman* ("Synopsis of Cutaneous Diseases," 1819) and succeeding English authors, and, moreover, that Bazin could never have read Bateman's excellent description, nor seen his plate. For under " Herpes" Bazin states that he has shown herpes iris et circine to be parasitic affections, and turning to his " Legons theoriques et cliniques sur les Aff"ections Cutan6es parasitaires" (1858) we find him dismissing herpes iris thus:
"Parfois, autour d'un cercle herp^tique, on voit se developper un autre cercle herpetique, et m6me, plus tard, un troisidme autour de ce dernier ; ces divers cercles concentriques peuvent off'rir des nuances varices et constituer I'affection decrite dans les divers ou- vrages de dermatologie sous le nom herpes iris."
In his lecture on the " Affections Gt'n6riques de la Peau," vol. i. (1862), Bazin makes a full confession of his mistake, and says he was led away by the writings of MM. Gibert, Cazenave, et Devergie, but he adds (p. 108) that, after consulting Bateman's work, " Je n'h^site pas a declarer que la description donn^e par Bateman de
- Bateman says Willan noted it as an erythema iris, having only seen the early
stage (p. 241).
