Acute Myelitis. Poliomyelitis. 157 



poisoning, as from ergot, smut, the poisons of the cryptogams 

 and bacteria of mouldy bread, musty fodder, spoiled meats, fish, 

 etc. ; also the poisons of lolium, vetch, lupin, astragalus, 

 oxytropis, arsenic, etc. 



Lesions. These consist in a yellow or pink discoloration of 

 the white and especially of the gray matter, and a special prom- 

 inence of the puncta vasculosa in the affected part. Swelling or 

 distortion of the part is not usual. This may involve only a 

 single gray horn, the two horns on the same side, the two in- 

 ferior horns, or all four at once, or the white matter adjacent 

 may also show the rosy tint, the large puncta, and a charac- 

 teristic softness and friability. Minute blood extravasations are 

 very significant. Microscopically examined leucocytes are found 

 in abundance in the perivascular spaces and in the neuroglia, 

 The neurons (nerve ganglia cells) are degenerated, being 

 cloudy, swollen, with enlarged nucleus, stain highly, and show 

 enlargement of the chromophile granules.' In a more advanced 

 stage the cell has an indefinite outline and the nucleus is in- 

 distinct and may fail to take a stain ; the chromophile granules 

 are irregular and do not radiate evenly from a centre and many 

 vacuoles appear. This may lead to fatty softening, or to fibrous 

 increase of the neuroglia, and sclerosis. 



Symptoms. These vary greatly in different cases according to 

 the part involved, the meninges or some special region of the 

 cord, to the essential cause of the inflammation and its acuteness. 

 Usually the attack sets in slowly in contradistinction to the 

 abrupt attack of congestion. Hyperthermia and rigor are 

 usually among the first symptoms, though in many cases hyper- 

 aesthesia is the most marked early symptom. The skin covering 

 the muscles which derive innervation from the affected section of 

 the cord is the most sensitive. This is often so extreme along the 

 vertebral column that percussion on the spinous processes or 

 pinching between the fingers and thumb causes the most pro- 

 nounced wincing and dropping of the back. Copland and 

 I,aposso have noticed that a sponge of hot water drawn along the 

 line of the vertebrae causes acute pain and contractions of the 

 muscles of the back and limbs, which are almost tetanic in their 

 force. This probably implies the existence of meningitis, since 

 the absence of rigidity of the muscles of the neck, back and 



