588 General Syniptoinatology of Diseases of tlie Brain, 



the reflex is most active in the dog, cat and sheep and least in the ox, the horse 

 occupying an intermediate position. It is as a rule more pronounced in young 

 animals. Eeflexes of the anconeus or gastrocnemius can scarcely ever be obtained 

 by striking their tendons under normal conditions. 



In pathological conditions reflexes may be either exaggerated, diminished or 

 entirely absent. The exaggeration of the reflex is recognized by spasms which are 

 more extensive and follow each other with greater rapidity. The opposite is the 

 case when there is a diminution of the reflex, but great care must be exercised in 

 determining them because vohmtary movements of the muscles may prevent the 

 occurrence of twitches owing to the fact that the animals have to be kept still for 

 a considerable length of time during the investigations. 



Disturbances of nutrition are observed, especially in the 

 later stages or in diseases of the brain of long standing. These 

 are for most part due to an insufficient quantity of food being 

 taken owing to severe disturbances of consciousness. 



The diagnostic importance of general brain symptoms is 

 that they indicate either a direct or indirect disease of the whole 

 brain, but they are of no value in localization of the disease. It 

 should not be forgotten that general symptoms of a moderate 

 nature may be due to functional disturbances of the brain, such 

 as occur in acute infectious diseases and such as ordinarily 

 occur in severe internal diseases. 



(b) Focal Symptoms. 



The comparative rarity of localized nervous diseases in the 

 domesticated animals and the primitive methods of in- 

 vestigation of the nervous system of animals adopted in earlier 

 times sufficiently explain the fact that our knowledge regarding 

 the localization of diseases of the brain and focal symptoms is 

 somewhat defective. A brief outline of the focal sjanptoms 

 based upon cases of disease that have been published more re- 

 cently and upon the animal experiments carried out by various 

 authors appears to be justified. 



As a general rule focal symptoms cause motor and sensory 

 disturbances. Motor disturbances are generally the more easily 

 observed and are evidenced either by paralysis or abnormal 

 movements. 



Motor paths (see fig. 78). Experimentation has shown that there are great 

 differences between the motor paths and centers in man and animals, and that the 

 differences become more pronounced the lower the animal is in the scale of de- 

 velopment. The peripheral motor path, the oldest in the vertebrata, begins at the 

 nerve cells in the anterior horn of the gray matter in the spinal cord or in the 

 nuclei of the cranial nerves and terminates in an end plat in a muscle fil)er. The 

 cells of origin of this path are connected with the central motor path. In the first 

 place they are connected with the subcortical or principal centers by means of the 

 extrapyramidal or principal paths ; further, with Monakow 's fasciculus between the 

 nucleus ruber (Nr) and the lateral column of the spinal cord on the opposite side, by 

 a fasciculus connecting the corpora quadrigemina (Cqu) with the ventral column of 

 the opposite side, paths from the pons (P) which pass partly to the lateral column on 

 the same and partly to the lateral columns on the opposite side, and finally a path 

 connecting Deiter 's nucleus with the ventral column on the same side. The subcortical 

 motor centers are connected by nerve paths with the motor cells scattered through the 

 cortex and arranged around the sensory centers. These paths, after arising in the 

 cortex converge towards the capsula interna and then crossing over pass to the 

 subcortical centers of the opposite side. 



