Some high-spirited animals, under extreme fatigue from overwork, sometimes become violent but resume their docility under rest and food.
In all cases we must know the normal of an individual animal to enable us to properly appreciate any apparent deviation from the psychic norm. No less essential is it to take into account the environment and treatment of the patient.
With regard to localization of cerebral lesions, Sequin thinks emotions are probably generated in the basal ganglia such as those of the pons and thalami, while inhibition depends on the anterior cerebral cortical convolutions.
DIAGNOSIS, SYMPTOMS AND THEIR IMMEDIATE CAUSES. LOCALIZATION OF LESION IN SPECIAL SYMPTOMS.
Spasm, pain, numbness—irritation. Paresis, paralysis, anæsthesia (constant)—destructive lesions. Both combined—variable symptoms, recurrent. Definite, fixed symptoms—structural lesions, usually progressive. Symptoms, variable as to place, time, subsidence and recurrence—functional lesions. Brain lesions. Pressure on brain—pain, spasm, nausea, dullness, blindness, stupor, coma, palsy. Congestion and anæmia synchronous. Lesions of cortex. Encephalic lesions—hemiplegia, with spasms, increased reflexes, spasms follow cranial nerves, vertigo, apoplexy, epilepsy, dementia, coma, little muscular atrophy, or dermal sloughing. Spinal lesions, paraplegia without spasm, reflex reduced or nil, follow spinal nerves, head symptoms less, much muscular atrophy, bed sores. Sensory and motor tracts, in crus cerebri, respiratory centres—inspiratory expiratory, inhibition. Salivation, sneezing, coughing, sucking, chewing, swallowing, vomiting. Cardiac centres, accelerating and inhibitory. Vaso-motor centre. Spasm centre. Perspiratory centre. Pons. Corpora quadrigemini, crura cerebri. Thalamus, corpus striatum. Cerebellum. Cerebral cortex: in ass; in dog. Spinal lesions: lateral half section: central anteroposterior, vertical section: superior columns: inferior columns: cervical lateral columns: respiratory tract: glycogenic centre: pupillary dilator: cardiac accelerator; vaso-motor, sudoriparous: centre for anal sphincter: for vesical sphincter: genital centre: vaso-motor and trophic centres: muscular sense tract: superior column and Goll’s. Table of phenomena from cord lesions.
In Irritation of nervous organs the symptoms (spasm, pain, numbness) are usually intermittent.
In Destructive Lesions of nervous organs the symptoms (paresis, paralysis, anæsthesia) are usually constant.
When irritation and destruction are associated the symptoms are variable and frequent. The characteristic symptoms of the two may coexist or succeed each other.
Structural Nervous Lesions have symptoms that are definite in their area of distribution, nature (spasm, paralysis) and permanency. Objective Symptoms predominate and the case is likely to be progressive and fatal.
Functional Nervous Diseases have symptoms of indefinite distribution, variable in character, with intermissions and spontaneous disappearances (as under marked excitement) and subjective symptoms predominate. They may, however, last for a length of time without change.