294 DISEASES OF THE SPINAL MARROW AND ITS MEMBRANES. 



the back and the peripheral pain are to be referred to the irritation of 

 the sensory nerves within the spinal canal, from the inflammation of 

 their envelopes. Tcaic spasms in the muscles of the back and extremi- 

 ties, causing opisthotonos and contraction of the limbs, are just as 

 constant symptoms as tne morbid excitement of the sensory spinal 

 nerves. These tonic spasms, which, as is well known, we may induce 

 artificially in animals, by irritating the spinal medulla with the in- 

 duced current, usually remit and exacerbate. The exacerbations are 

 not, as in tetanus, induced by irritating any part of the skin, but by 

 movements of the spinal column, a fact which indicates that the tonic 

 spasms in meningitis spinalis are not due to increased reflex excitabil- 

 ity, but are direct results of irritation of the motor nerves from the 

 inflammation of then: envelopes. The rigidity and tension of the body, 

 which prevent the patient, who is not at first paralyzed, from moving, 

 are from time to time interrupted by convulsive starts. If the respira- 

 tory muscles participate in the tetanic rigidity, breathing becomes im- 

 possible, and the patient soon dies as a consequence. If the res- 

 piratory muscles remain unaffected, there is occasionally a gradual im- 

 provement ; but more frequently paraplegia is developed, or the fever 

 increases, and the patient succumbs to the paralysis, which advances 

 to the medulla oblongata, or to the exhaustion induced by the fever. 



In the chronic form of inflammation of the pia mater, whose symp- 

 toms we described with those of hydrorhachis acquisita, since we con- 

 sider a distinction between them as impracticable, the pain in the back 

 is usually inconsiderable and is easily overlooked. On the other hand, 

 at the onset of the disease, the pain in the extremities is often such a 

 prominent symptom, that the affection is mistaken for peripheral rheu- 

 matism. The most important symptoms are those of paralysis, which, 

 commencing in the lower extremities, extend to the bladder, rectum, 

 and subsequently to the upper extremities. The paralysis is usually 

 incomplete at first, and only gradually increases to complete para- 

 plegia ; along with it there is usually a feeling of formication and fur- 

 riness in the lower extremities, the precursor of anaesthesia, which, 

 however, rarely attains a high grade. In some of these cases the 

 paraplegia develops quickly, occasionally in a few days after being 

 preceded only for a short time by pain, which is considered as rheu- 

 matic (hydrorhachis rheumatics). The paralysis then often remains 

 stationary at the height it has attained, or may entirely disappear. In 

 other cases the paraplegia develops more slowly and insidiously. In 

 such cases the hope of a permanent decrease of the paralysis is 

 slighter, although the disease almost always shows remarkable varia- 

 tions in its course. Most patients die sooner or later from extension 

 of the paralysis to the medulla oblongata, from bed-sores, or from 



