GENERAL PART OF EXAMINATION. 51 



7 Foot eczema, produced by potato residue, swill and brewer 

 gram feeding, is a vesicular eczema occurring on the hind legs of 

 the ox^ The vesicles rupture soon after formation and their con- 

 tents dry to thick yellow scabs. The hair of the affected parts 

 stands erect and part of it falls out. In most instances the eczema 

 reaches no higher up the legs than the hock, but may spread to 

 the body or involve the anterior limbs. 



11. Skin Diseases Due to Animal Parasites. 

 The common skin parasites are: 



1. Lice or Pediculidae (Haematopinus asini, eurysternus 

 urius, etc.) ' 



2. Bird lice or Mallophaga (Trichodectes equi, scalaria etc)* 



3. Louse flies or Hippoboscidae (Hippobosca equina, Meloph- 

 r.gus ovis). 



4. Ticks or Ixodidae (Boophilus bovi.^) Texas cattle tick 



5. Fleas or Siphonaptera (Ceratopsyllus serraticeps of dog 

 Pulex irmans of man). ^' 



6. Bird ticks or Gamasidae (Dermanyssus avium, D. gallinae) 



7. Mites or Acarina (Chorioptes. symbiotes, horse, ox, goat, 

 etc.). (Psoroptes communis, horse, ox, sheep, etc.). (Sarcoptes' 



■equi, cams, suis, cati. etc.). (Sarcoptes mutans of fowl) (Acarus 

 folhculorum or Demodex folliculorum, var. canis, suis, etc.). 



and reShlP^Th^".-!!^" '""^I" ^^"0P°" Pallidum, is remotely related to the trichodectes. 



