768 NEUROSES. 



their main and essential characters merely local, they may in 

 process of time become associated with general disturbances 

 and conditions of ill-health, and with the appearance of similar 

 growths in other and different structures of the body. This 

 may occur either as part of a general cachexia, as the result of 

 the influence of serious local changes on systemic activity, or 

 from the infective power of the primary local disease. 



In the horse, diseases of this class are rare, and when seen 

 are usually in the form of some varieties of cancer or sarcoma. 

 The growth or development of these malignant conditions is 

 usually slow ; but when interfered with they may show un- 

 looked-for activity, with a liability when removed to recur. 

 Their description and treatment belong rather to the province 

 of surgery than medicine. 



Class III. Neuroses. 



It is probable that with a more extended and exact dermal 

 pathology many diseases which are presently grouped under 

 other classes may yet be placed under that of disturbed inner- 

 vation. 



At present, although satisfied that with many inflammatory 

 affections, disturbance of nerve-function coexists, often as a 

 secondary, but sometimes as a primary condition, still, none 

 are included here as disorders of the nervous element of the 

 skin, which may be differentiated by any distinct elemental 

 change. 



The primary affections which may be regarded as comprised 

 under cutaneous neuroses are ' Increased Sensibility,' ' Dimin- 

 ished Sensibility,' ' Perverted Sensibility.' 



The latter of these, known as ' Pruritus,' is probably that 

 which most frequently engages our notice. 



When remarking upon inflammatory skin diseases, as eczema, 

 prurigo, etc., irritability of the parts and itching were noticed 

 as prominent features. These may also occur in recovery 

 from certain fevers, from the contamination of the blood by 

 the circulation in it of waste materials; in other systemic 

 diseases, as rheumatism ; and in certain local affections, as liver 

 and kidney diseases. 



The more j)urely nervous character of pruritus, however, is 

 shown apart from the existence of either general or local 



