INTERNAL DISEASES 417 



such as gout and obesity, in man are not unknown in domestic 

 animals; dogs suffer from the former, and also parrots, when 

 too closely confined and too richly fed. Dogs, cattle and sheep 

 suffer from the latter, and also pigs. Scrofula, frequent in young 

 horses and swine, is, as in man, no definite disease, but a general 

 term denoting a number of morbid symptoms which are due 

 to tuberculosis (Friedberger and Frohner). Finally, there is 

 Addison's disease a chronic ailment, causing general cachexia 

 and pigmentation of the skin, produced by cancerous, tubercu- 

 lous or other changes in the suprarenals. No notice of this 

 disease has hitherto appeared in veterinary text-books, and 

 for the present therefore it must be regarded as peculiar to 

 man. 



Diseases of the Skin. We will conclude the section on in- 

 ternal diseases by considering the diseases of the skin which 

 will form a link with the diseases of a surgical nature. Our dis- 

 cussion of the infectious and parasitic diseases of the skin left for 

 further consideration a series of other pathological conditions of 

 the skin, which partly resemble those affecting man, and partly 

 differ from them. The same atrophy of the skin which leads in 

 old men to the disappearance of the pigment, and also of the 

 hair itself, is also met with in old animals. In animals, too, 

 hypertrophy of the papillae leads to warts and polypi, which are 

 preceded by a hypertrophy of the cutis. On the other hand, 

 Elephantiasis arabum and Ichthyosis, which depend on hyper- 

 trophy of the epidermis, are peculiar to man. 



The various forms of inflammation of the skin show many 

 points of resemblance between man and animals. Sheep, swine, 

 dogs and horses often suffer from erythema ; cattle, horses, dogs 

 and swine from urticaria ; and these animals, with the excep- 

 tion of swine, also develop pemphigus and acne. Schmidt 

 has reported a case of psoriasis in an orang-utan and in an 

 ape. 



On the other hand, the well-known text-book of Friedberger 

 and Frohner says nothing about herpes, impetigo, ecthyma or 

 prurigo, so that for the present we must conclude that these 

 conditions are peculiar to man. 



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