ON THE SENSORY DISTURBANCES 137 



recondite subjects in the whole category of nervine disease, 

 as it is met with, especially in the peripheral aspect of the 

 nervous system. Itching and pain, perverted, or abnormal, 

 aesthesia, primary and secondary, original and resultant, 

 become the symptomatic finger-posts guiding us along 

 the Aesculapian way, so to speak, and which, when utilised 

 with a due appreciation of, and dependence on, their 

 intrinsic value in the detection of cause and effect, will 

 illuminate and render more tractable the direction of some 

 of its obscure windings and less explored byeways, amid 

 the uncertainty surrounding the genesis and progress of 

 many of the diseases of the peripheral aspect of the 

 systemic, as well as the sympathetic, nervous systems 

 individually and conjointly. Abolished, disturbed, and 

 perverted sensation may often begin and end as simple 

 sensory phenomena, indicating only the most ephemeral 

 interference with the prevalence of normal sensory function, 

 and nothing but a temporary, and generally mechanical, 

 impediment to the operation of the normal sensory 

 physiological conditions and factors at work in the causa- 

 tion of afferent, or sensory, nervine genesis and conduction 

 the condition disappearing on the removal of the 

 impediment and the restoration of the neural patency 

 of the implicated nervature. When, however, as it no 

 doubt many times is, the impediment to normal sensory 

 innervation is more or less permanent, we may regard the 

 discovery of what the impediment is as affording the 

 necessary indicator of the line, or lines, of treatment to be 

 adopted in the removal of the diseased condition, and the 

 restoration of both healthy structure and function. 



Thus pain, and in fact every disturbed sensory pheno- 

 menon, becomes of the greatest value to the clinician, in 

 safely guiding him along correct pathological lines, until 

 it becomes possible for him to read, and determine, in 

 altered and disturbed anatomical, histological, and physio- 

 logical conditions, or characters, the history and progress 

 of the diseased state regarding which his advice has been 

 sought, and consequently the discovery of the most 

 scientific indications for the treatment to be pursued. 



No doubt in estimating the practical value of pain and 

 disturbed sensation, in the work of diagnosis, prognosis, 



