188 DISEASES OF THE BRAIN. 



symptom of irritation of the brain. Without understanding the pro- 

 cess in the central organs, by which the motions of vomiting are brought 

 about, we nevertheless know that it is artificially induced in animals 

 by dividing the vagus, and then irritating the central end. 



The above symptoms of morbid excitement, and of increased, 

 diminished, or lost excitability of the brain, which we shall also meet 

 in many other cerebral diseases, occur in the most varied groups ill 

 cerebral hyperaemia. When speaking of general convulsions, we called 

 attention to the constant coincidence of this symptom, which is due to 

 morbid increase of excitement in the medulla oblongata, with loss of 

 consciousness, which indicates loss of excitability of the other central 

 ganglion-cells and nerve-filaments ; and we must add that, not unfre- 

 quently we meet other complications of symptoms of irritation with 

 those of paralysis, in hyperaemia of the brain. For instance, the power 

 of motion is occasionally lessened while the patient is under great 

 mental excitement, complaining of headache, sparks before the eyes, 

 etc. Hence, from the state of the pupil, the slowness or rapidity of the 

 pulse, etc., we may recognize the state of excitement in which the 

 central organs of the nerves governing these states are at the time, 

 but we cannot come to any conclusion regarding the condition of other 

 parts, or of the entire brain. The variety of appearances, resulting from 

 the different combination of symptoms, is so great, that Andral has 

 represented, as different forms, eight different combinations of symp- 

 toms which appear in cerebral hyperaemia. We shall only give a 

 short account of the most frequent and important forms. 



In many cases of hyperaemia of the brain, disturbances of sensibility, 

 of an irritating character, are the most prominent symptoms. Such 

 patients complain of the head feeling contracted, of more or less severe 

 headache ; they are sensitive to bright light and loud noises ; have 

 flashes of light before the eyes, and noises in the ears. They go to 

 sleep with difficulty, and the sleep is disturbed by unquiet dreams. In 

 severer cases, there are often dizziness and a feeling of formication in 

 the extremities. The face and conjunctiva are usually reddened, the 

 pulse full and rapid. But we must not consider these symptoms as 

 constant ; for, in the most dangerous cases of hyperaemia of the brain, 

 in those induced by excessive mental labor, continued night-watching, 

 etc., the amount of blood in the external organs does not at all cor- 

 respond to the supply in the brain ; and frequently the conjunctiva is 

 not at all injected in such patients, nor is the face flushed ; on the con- 

 trary, it is pale. Occasionally the above symptoms only last a few 

 minutes. In some patients a few glasses of wine, or some hot coffee, 

 suffice to induce these symptoms of " congestion in the head ; " while 

 they remain exempt from them if they keep quiet, and avoid excitement 



