1893.] An Extreme Case of Parasitism. 349 
identical, are produced by other species of the Sarcoptes 
derived from horses, dogs, cats, camels, sheep and rabbits.” 
Such cases are, however, rare. 
It is, perhaps, unnecessary to add that the mite is never 
found in the body, only upon it, never in the organs or in the 
blood. 
The human itch mite is perhaps coeval with man. It has 
certainly always existed as far back as written history goes. 
Hebra, for good reasons, believes that many of the afflictions 
of the Israelites, as mentioned in the Old Testament, were 
nothing other than the itch.” Aggravated forms no doubt 
frequently occurred. Geologically speaking, the mites, as a 
group, are of recent appearance (Garman)." 
The itch is, at the present time, becoming one of the rarer 
afflictions of mankind—like all filth diseases, it is gradually 
disappearing. 
(In his Atlas of Skin Diseases (p. 319), Doctor R. W. Taylor 
says: “ Until a few years ago, scabies was a rather uncommon 
disease in this country, but it has been noticed that in the 
various large cities and in some small communities, there has 
been of late, a remarkable increase in its prevalence.” Italics 
mine. 
In a recent letter to the writer, he expresses the belief that 
this is mainly due to the influx of Russian and Polish immi- 
grants. 
Cases are seldom seen outside of the slums of large cities ; 
but it sometimes happens that if a case occur, say in a small 
town where none had appeared for years, perhaps half of the 
population becomes affected before its true nature is known, 
and appropriate remedies are applied. Vigorous medical treat- 
ment soon blots out an epidemic. 
In an ordinary, acute or epidemic case of itch, the number 
of mites is quite small, probably not exceeding one hundred 
adult animals. 
® Taylor, ‘Atlas of Skin Diseases.” P. 327. 
10 Hebra, “ Diseases of the Skin.” P. 164-166. 
1 «Insect Life.” Vol. IV., P. 182. 
