Cerebro- spinal Meningitis 121 



encapsulatus). This is frequent in the mouths of healthy per- 

 sons so that some additional accessory cause must be invoked to 

 increase the susceptibility or lessen the protective power of the 

 tissues. This has been thought to be found in the concurrent 

 presence of other bacteria, the staphylococcus pyogenes aureus, 

 pneumobaccillus of Friedlander and the streptococcus pyogenes. 

 Mosny appears to have established this for the staphylococcus in 

 the case of rabbits. With a given dose of the micrococcus pneu- 

 moniae death was always delayed for a fortnight, while with 

 the same dose thrown into one thigh, and the staphylococcus 

 aureus in the other, the rabbit died in one day. This enhanced 

 potency resulting from the presence of the golden staphylococcus 

 has been invoked to account for the germ making its way from 

 the mouth to the brain in cases of otitis, suppuration of, the 

 Eustachian tube, tonsilitis or nasal catarrh. These remarks are 

 intended to be suggestive, rather than conclusive, as we haive 

 as yet no certainty that cerebro-spinal meningitis in the horse 

 is caused by the same germ as it is in man. 



Lesions. The lesions are usually those of leptomeningitis, or 

 congestion of the brain and spinal cord and often effusion into 

 the ventricles, with a serous exudation under the pia mater or 

 into the arachnoid cavity. This may be transparent and yel- 

 lowish, or grayish and turbid, or milky. In the sheep, Roloff 

 has found purulent products under the pia mater, around the 

 roots of the spinal nerves, and in the surface layers of cerebral 

 gray matter. The marked hyperaemia on the surface of the 

 gray matter is a striking feature, and circumscribed areas of ne- 

 crotic nervous tissue and softening are not uncommon. Pete- 

 chise are frequent on the meninges, the brain, heart, lungs and 

 kidneys. Granular and fatty degenerations are also met with in 

 these parenchymatous organs. The blood may be dark and 

 liquid or diffluent. 



Symptoms in the Horse. The mildest attacks are manifested 

 by paresis, or loss of perfect control over the limbs, or loss of 

 power over the tail, impairment of appetite and some difficulty of 

 swallowing, together with some congestion or reddish brown dis- 

 coloration of the orbital and nasal mucosae. In other cases 

 paralysis of one or more limbs may supervene but without' 

 marked fever or coma. 



