498 



DISEASES OF THE SKIN. 



they are developed rapidly.^ The adherents of this microbic theory 

 go decidedly too far. However, the bacteria must act here, as in 

 all the various phlegmasias, by increasing the inflammation. The 

 question as yet undecided is, whether common fungi, found upon 

 the surface of the skin, play a pathogenic rôle, or are met with 

 there by accident. Concerning those cases where eczema ap- 

 pears without having been preceded by any cutaneous irritation, 

 internal causes have been incriminated, especially ingestion of a 

 poor quality of food, digestive troubles, plethora, weakness of 

 constitution, etc. But these etiological influences probably act 

 only as predisposing conditions. The cause determining eczema 

 seems to be in all cases a direct irritation of the cutaneous integu- 

 ment. 



[From an anatomical point of view we find that the skin of dogs 

 is naturally predisposed to eczematous diseases, but other condi- 

 tions must necessarily be present : first, excessive alimentation, an 

 affliction which all house dogs are called upon to endure; secondly, 

 insufficient exercise, which is always associated with the first con- 

 dition ; thirdly, uncleanliness. These are irresistible influences 

 constantly at work in the production of this disease. — w. L. z.] 



Symptoms. Symptoms of acute eczema in the dog are of the 

 most complete kind ; it is difficult to give a general description of 

 their nature. They vary much, according to the period at which 

 they are observed. 



1. In the initial phase, which often passes imuoticed, we find 

 upon the skin w^hich is deprived of pigment light-red spots, of a 

 diameter varying from a pin-head to a pea; their coloration be- 

 comes gradually darker, and a small papule is developed in the 

 centre ; these spots become enlarged little by little, and also con- 

 fluent ; the skin undergoes tumefaction on their surface ; it also 

 becomes thickened, turgescent, and very hot; the hairs are erect 

 in tufts. The slightest touch occasions pruritus, and these com- 

 pressions, even when slight, produce pain. At a more advanced 

 stage we may observe erythema or erythematous dermatitis. These 

 characters are sometimes greatly modified by frictions and the 



1 We may find microphytes as numerous as they are various, and without any 

 pathogenic rôle, upon the surface of the skin and sometimes quite deeply in the 

 excretory canals. When we wish to study vesicular and pustular lesions of the skin 

 from a bacteriological standpoint, it is proper 'to press the liquid to be examined or 

 cultured from the deep parts of the derma and not through the epidermic layer; 

 "without this precaution the collected product is almost always impure. — n. d. t. 



