624 Injuries and Concussion of the Brain. 



the cranium with simultaneous hemorrhage into, and more or 

 less extensive bruising of the brain tissue. Lesions of the skin 

 may be quite trifling or even unrecognizable, and there may be 

 bruising of the brain and membranes without apparent injury 

 to the cranium. At the instant that the injury occurs the 

 brain tissue receives a shock and is bruised or even destroyed 

 by the concussion or the forcing inwards of portions of the 

 bones. There is a sudden rise in the intracranial pressure. As 

 a rule, injuries to the brain and membranes cause symptoms 

 of a general nature, but in a proportion of cases there are local 

 symptoms. 



Anatomical Changes. Fracture of the bone occurs either at 

 the place where the blow is delivered or at some other part of 

 the cranium. In the horse fracture of the base of the cranium 

 is especially likely to follow a blow on the poll or a fall onto 

 the chin, because the base of the cranium is less resistant, and 

 at the moment of the blow is forced against the rigid cervical 

 vertebrae. 



The lesions in the brain vary from case to case, and as a 

 rule are found at the place where the injury has occurred, but 

 in other cases they are in parts of the brain remote from the 

 seat of injury. As a rule the lesions of the intracranial struc- 

 tures can l)e recognized by hemorrhage of the anterior portion 

 of the brain, base, medulla, or cerebellum and may even extend 

 into the lateral ventricles. In cases where the bones are in- 

 jured, and even in cases where there is no such injury, a larger 

 or smaller portion of the brain may be reduced to a pulp-like 

 mass mixed ^^dth blood. 



In many cases there are no lesions visible to the naked 

 eye, in spite of the fact that severe nervous symptoms may 

 have been presented by the animal during life. Such cases are 

 generally included under the term concussion of the brain, it 

 being supposed that the temporary or permanent disturbances 

 of function of the nerve elements are due to molecular altera- 

 tions of the nerve tissue and not to gross lesions. Experi- 

 ments by Westphal, Schmaus, Oppenheim and Bikeles, and two 

 observations of Hutyra & Marek show that in cases where the 

 central nervous system is apparently uninjured there is ex- 

 tensive degeneration of the nerve tissue, and sometimes small 

 hemorrhages showing that there has been some tissue disor- 

 ganization. There are, therefore, no grounds for distinguish- 

 ing between concussion and contusion of the brain. 



Symptoms. Symptoms of general disturbance make their 

 appearance, as a rule, immediately after the infliction of the 

 injury. In other cases, some minutes elapse before their ap- 

 pearance, and it may be even an hour or more. This is espe- 

 cially the case when the disturbances are exclusively or mainly 

 due to hemorrhage. In a case in a horse recorded by Hoifman, 



