ITCH MITES, 301 



CASE crusts are extraordinarily hard, almost like horn, and if they are 

 softened by steeping in water and placed under the microscope, 

 they seem to be composed in some sort only of the skeleton skins 

 of dead mites, superposed and bound together by a viscous 

 matter; in truth, it is a little world of animalcules, one generation 

 upon another, and their skeletons compose this most remarkable 

 form of " Spedalskhed." This description does not accord with 

 the usual work of a Sarcoptes ; but Messrs. Boeck and Danielssen 

 seem to have had no doubt on the subject, and only to have had 

 a difficulty in making up their minds whether it was the common 

 S. scabiei or a different species. They inclined to the latter, in 

 which view they were confirmed by the opinion of Norwegian 

 naturalists, to whom they showed specimens and a figure. That 

 figure has been published in their work, but we have not seen it, 

 and only obtained the above knowledge of its contents from M. 

 Furstenberg's account of the literary history of the itch mites 

 given in his valuable work. Die Kratzmilben. 



The description, however, quite agrees with that of subsequent 

 observers who have met with the disease. Fuchs describes two 

 cases, and M. Second-Fereol one that he observed in Paris, which 

 place the symptoms in even a worse light than those recorded by 

 M. Boeck. 



The complaint, as described by him, was chiefly seated in the 

 hands and fore-arms, and was characterised by crusts of a dirty 

 yellow colour of considerable thickness, especially on the hands, 

 where they formed a stratum that reached, and even exceeded 

 half an inch in thickness. They were traversed by broad and 

 deep cracks, which corresponded more or less with the articular 

 folds. The bottom of these cracks was moist but whitish, and by 

 no means bloody ; the fingers and back of the hand covered by 

 this sort of cuirass, looked like the bark of a rugged rifted tree, 

 but of a yellow colour. On the rest of the body it lost, or 

 perhaps it would be more correct to say, had not yet attained, 

 its character of continuous envelope, but it was dispersed over 



