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of which both these sets of factors are implicated. It 

 may, indeed, be said that the majority of skin diseases are 

 dependent upon both for their causation, as we may see in 

 cases of erythema in a rheumatic subject, in connection with 

 dyspepsia ; eczema in a gouty subject, dependent upon mal- 

 assimilation ; psoriasis in a scrofulous subject, dependent 

 upon alteration of the normal healthy character of the 

 blood ; pruritis in connection with gout, hepatic derange- 

 ment, or diabetes. Here, for example, in cases of erythema 

 in a rheumatic subject, in connection with dyspepsia, the 

 dyspepsia is an internal cause, dependent more or less upon 

 the rheumatic diathesis ; mal-assimilation an internal cause, 

 dependent upon the gouty diathesis ; alteration of the normal 

 condition of the blood dependent upon the scrofulous 

 diathesis, and so on ; the first producing erythema, the second 

 eczema, and the third psoriasis : and in this connection it 

 may be well to emphasise the axiom that the true cause of 

 the state of any given disease is made up of a number of 

 phenomena or agencies in combined operation. Excluding 

 such non-hereditary agents as the acute specific poisons, 

 medicinal substances, deleterious articles of food, etc., which 

 may produce skin disease, we still have amongst the internal 

 causes those more or less depending upon heredity, including 

 gout, rheumatism, syphilis, leprosy, certain conditions in 

 which injurious substances enter the current of blood, or 

 are retained in it in undue proportions, as dyspepsia, mal- 

 assimilation, functional uterine disturbance, and various 

 morbid conditions of the liver, kidneys, and intestines ; also 

 certain conditions of the nervous system, producing hyper- 

 semia and urticaria, herpes, pemphigus, anaesthetic leprosy, 

 and that impaired functional power involving loss of control 

 over the skin nutrition, allowing morbid action of all kinds 

 to take place more readily. 



