INFLAMMATION OF THE BRAIN 239 



skull is depressed, cracked or splintered, pressing on the brain substance, 

 and causing more or less extensive hemorrhage of the interior of the cavity 

 of the brain. The hemorrhage is generally most extensive in the dura 

 mater, between it and the cranium, but it may also be observed between 

 the pia mater and the cerebral cortex or even in the brain substance itself, 

 and while under the microscope we may not find any change in the brain 

 substance in spite of the fact that there is grave cerebral disturbance, it 

 has been called concussion of the brain and is due to a mechanical displace- 

 ment of the brain substance and the fluids of the brain are compressed in 

 the ventricles. 



Clinical Symptoms and Therapy. — Any pronounced traumatism of this 

 kind generall}' causes death. There may be bleeding from the nose or ears, 

 with acute congestion of the conjunctiva. Give the animal absolute rest, 

 cold local applications, surgical treatment of the injured portion of the 

 skull, and also the injured soft tissues, evacuation of the faeces and the 

 administration of stimulants. 



Inflammation of the Brain. 



From a pathological standpoint we have to make a distinction be- 

 tween inflammation of the hard cerebral substance (pachymeningitis) 

 and that of the soft cerebral membrane (leptomeningitis). This classi- 

 fication, however, need not be used in a clinical way, because in the dog, 

 the described forms run their course with the same symptoms. 



Etiology. — Inflammation of the brain may be the result of some trau- 

 matism, or from sunstroke, great physical excitement, over-exertion, etc. 

 This condition also occurs secondarily from disease, such as distemper and 

 pyaemia, causing suppuration within the skull, in inflammation of the frontal 

 cavities as a result of the irritation caused by the presence of parasites; in 

 purulent inflammation of the ear (in connection with external otitis), 

 and from abscess of the middle ear and orbital cavity. Inflammation of 

 the brain is seen in certain infectious diseases, especially distemper, and is 

 also associated in rare instances with pharyngitis, bronchitis, gastritis, 

 and also from unknown causes. In dogs that died from inflammation of 

 the brain, Trolldenier found a pathogenic streptothrix, allied to the group 

 of actinomycetes. Over-exertion and great physical excitement are also 

 said to be predisposing causes of this disease. 



Pathological Anatomy. 1. Inflammation of the Dura Mater. Pachy- 

 meningitis. — The tlura mater is covered with a numl)er of small hemor- 

 rhages. It is loose, easy to tear, and over the surface is a collection of 

 bloody, purulent masses of exudation. In the later stages of the disease 

 we see a circumscribed or extended thickening and adhesion of the cov- 

 ering to the base of the skull or to the soft cerebral-membrane. 



