174 CEREBRO-SPINAL FEVER. 



complication of that fever ; this view I for long entertained. 

 Still evidence is not wanting to show that, although such 

 phenomena as are characteristic of this fever may be observed 

 in certain manifestations of distem'per, there are still many in- 

 vasions of 'cerebro- spinal disease' more easily explicable on 

 the supposition that the disturbance is an abnormal condition 

 per se, and that Avhatever may be the immediate inducing 

 factor, it is specific and distinct. 



The febrile symptoms, when existing in this disease, seem to 

 be directly related to the local lesions as a result or sequence, 

 and are not developed as the effect of the blood-contamination 

 direct, the inducing agent operating primarily on the nerve- 

 centres. 



The cause or causes of this disease, which comports itself 

 in most respects like other manifestations of that entire class 

 which owe their existence to the entrance into the animal 

 body of a specific poison, are not understood. 



The predisposing conditions do not, as in many other 

 diseased states, seem intimately connected with indifferent 

 sanitation or defective food-supply ; probably with overwork 

 and climatic disturbances, although these are not at all 

 definite. 



In America, where it is more generally distributed and more 

 frequently encountered, dietetic errors have by many been 

 credited with its production, particularly under certain condi- 

 tions, as the excessive use of Indian corn. 



h. Anatomical Characters. — The most obvious and exten- 

 sive of the structural changes are connected with the mem- 

 branes of the brain and spinal cord, and are indicative of 

 inflammatory action. 



These changes are not always in direct relation to the 

 length of the disease or its severity. In all there is hyperemia 

 of the pia mater, Avith often a congested state of the entire 

 vessels of the cranium and spinal canal, and the presence of 

 an extra amount of fluid of a turbid character in the sub- 

 arachnoid space; occasionally there are htemorrhagic spots 

 on the dura mator, and a gelatiniform and feebly organized 

 material betAveen the arachnoid and pia mater. This latter 

 material may exist over the posterior and superior convolu- 

 tions of the cerebrum and cerebellum, but is oftener encoun- 



