148 PHYSIC 



viz. the irritation of the nervous structures involved, an 

 increased blood supply to their surrounding non-nervous 

 structures, the disturbance of the textural condition of 

 these structures, as well as the neighbouring cellular and 

 connective tissues, with the consequent and subsequent 

 disturbance of the functional and textural integrity of the 

 true nerve elements of the nerves involved. 



The violence, the frequent repetition or the long con- 

 tinued incidence of these morbid phenomena determine 

 the nature and extent of the attack and its probable 

 termination. 



Thus the attack of neuritis may be acute or chronic, 

 local or general, and it may be characterised by all degrees 

 of intensity between acute and chronic, and with a distri- 

 bution varying between local and general, the general 

 being usually recognised as polyneuritis, a condition of 

 highly complicated disease, which is very often associated 

 with the nerve phenomena of alcoholism, arsenicalism, etc., 

 and other toxic conditions of the blood, and consequent 

 disturbance of its circulation amid the proper nerve ele- 

 ments. Besides the instances of neuritis due to toxis of 

 the cerebro-spinal lymph, and consequent irritation of the 

 dermic structures and musculature into which or through 

 which that toxic lymph is passed, we find that the purely 

 nervine elements of the nervous system also become 

 saturated with the toxic agent, in certain cases, with the 

 effect that such affections as dermatitis and hyper-keratosis 

 may arise on the afferent or sensory aspect of the systemic 

 nervous system on the one hand, and disturbances of the 

 nutrition and function of the voluntary musculature or 

 afferent aspect on the other. 



The forms of neuritis emanating from central nervine 

 toxis may thus be divided into extrinsic and intrinsic in 

 accordance with the order of involvement of the cerebro- 

 spinal contents or elements, the fluid or lymph elements 

 representing the former, and the proper nervine elements 

 the latter. 



