Sarcoptidce , or Itch Mites 
75 
diet, or ‘‘bad blood.” This was in spite of the fact that the mite was 
known to Mouffet and that Bonomo had figured both the adult and 
the egg and had declared the mite the sole cause of the disease. In 
1834 the Corsican medical student, Francis Renucci, demonstrated 
the mite before a clinic in Saint Louis Hospital in Paris and soon 
thereafter there followed detailed studies of the life history of the 
various itch mites of 
man and animals. 
The disease is a cos¬ 
mopolitan one, being ex¬ 
ceedingly abundant in 
some localities. Its 
spread is much favored 
where large numbers of 
people are crowded to¬ 
gether under insanitary 
conditions and hence it 
increases greatly during 
wars and is widely dis¬ 
seminated and abundant 
immediately afterwards. 
Though more commonly 
to be met with among 
the lower classes, it not 
infrequently appears 
among those of the most 
cleanly, careful habits, 
and it is such cases that 
are most liable to wrong 
diagnosis by the physi¬ 
cian. 
Infection occurs solely through the passage, direct or indirect, 
of the young fertilized females to the skin of a healthy individual. 
The adult, oviparous females do not quit their galleries and hence 
do rot serve to spread the disease. The young females move about 
more or less at night and thus the principal source of infestation is 
through sleeping in the same bed with an infested person, or indirectly 
through bedclothes, or even towels or clothing. Diurnal infestation 
through contact or clothing is exceptional. Many cases are known 
of the disease being contracted from animals suffering from scabies, 
or mange. 
08 . Scabies on the hand. From portfolio of Dermo- 
chromes by permission of Rebman & Co., of 
New York. Publisheis. 
