772 DISEASES OF ACCESSOKY ORGANS AND STRUCTURES, 



forms of this disease there does not appear any structural 

 change of either the gland-structures or the skin-tissues 

 proper which surround these ; the disturbance is purely func- 

 tional, and consists in an increased amount — steatorrhoBa — or 

 sometimes an altered character — allosteatodes — of the 

 sebaceous fluid. When increased in amount merely, the secre- 

 tion is often more watery than natural, while the varieties in 

 character are usually as to consistence, colour, and mode of 

 comporting itself 



When the abnormal conditions proceed beyond mere dis- 

 turbance of function, alterations in amount or of the character 

 of the secretion, these are shown first by infiltration of inflam- 

 matory products about and around the hair-follicles and 

 sheaths, with the formation of pus. With the swelling con- 

 sequent upon the periglandular inflammation and infiltra- 

 tion, the pus which is developed at length finds its way to the 

 surface, collecting and forming cakes in conjunction with the 

 altered sebum and epidermic cells, the changes taking place in 

 these latter conferring upon the mixed discharges a peculiar 

 and characteristic smell. 



The congestion or hyperemia not being relieved, hyper- 

 trophic changes take place in the papillary layer of the skin 

 and in the subcutaneous connective-tissue ; the hyperplasia 

 of the papillfe, combined with the perifollicular suppuration 

 and hypertrophy of the underlying fibrous tissue, tending to 

 the production of the well-marked irritable-looking projections 

 bathed in purulent fatty fluid known as 'grapes.' 



c. Causation. — This is to be looked for as proceeding from 

 influences both general and local, influences operating from 

 within as well as from without the animal. 



Steatorrhcea, Seborrhcea, or Erysipelatous Impetigo is always 

 found in situations where activity in the cutaneous glands is 

 expected to be considerable ; but this increase in function 

 seems, in direct proportion to their activity, to render them 

 liable to be disturbed by causes afl'ecting the general health 

 as well as by local unfavourable agencies. For its frequent 

 appearance in certain individuals and families it seems largely 

 indebted to constitution and inherited tendency. We find it 

 more frequently in horses of a lymphatic temperament, of 

 sluggish action, with excess of connective-tissue and abund- 



