Page:The American Cyclopædia (1879) Volume III.djvu/210

 204 BRAIN (DISEASES) In the first kind, the difficulty consists in the loss of the memory of words ; in the second kind, the difficulty seems to lie in the inabil- ity to coordinate the movements necessary to speech, the memory of words heing preserved. Aphasia of either kind may be complete, when speech is entirely lost, or there is more or less impairment of the power of speaking. Fre- quently the vocabulary of the patient is limited to a few words, perhaps a single word, uttered whenever an attempt is made to speak. Thus, patients may be able to say only yes or no, and this is said in answer to any question. It is not easy to determine, in cases of aphasia, to what extent, if at all, the mental powers are affected ; but it is certain that complete aphasia may exist while the faculties of the mind, aside from speech, are not materially affected. As already stated, aphasia may be incidental to different structural lesions, namely, hcemorrhage into the substance of the brain, softening from embolism or thrombosis, cerebritis, induration, and tumors. Generally it is associated with hemiplegia, and the paralysis is usually on the right side, the local affection of the brain being situated in the left hemisphere. And now a re- markable fact is to be stated : the lesion giving rise to aphasia in the great majority of cases is seated in a particular portion of the left cerebral hemisphere, namely, the posterior part of the third convolution of the anterior lobe of the cerebrum. This fact has led to the supposition that the portion of the left hemisphere first named is to be regarded as the seat of the fac- ulty of language ; but, as opposed to this, al- though the rule is as stated, there are some exceptions to it. Evidently, if the faculty of speech depended on the integrity of a particular part of the brain, that part should be affected in all cases of aphasia. Aphasia is generally a symptom of a lesion of some kind ; and it is then almost always persistent. There may, however, be some improvement as regards speech, al- though recovery do not take place. In some cases it is apparently dependent on a functional condition, and it is then recovered from. Aside from the measures of treatment which may be indicated by the nature of the lesion with which it is associated, or the circumstances connected with it when it is functional, efforts to speak on the part of the patient should be enjoined. Something may be accomplished by systematic endeavors to recover the memory of words or the power of coordinating the movements in- volved in speaking. VI. FUNCTIONAL DISOB- DEBS. The term functional disorder, as now used, denotes a morbid disturbance of functions taking place independently of either inflamma- tion or any palpable alteration of structure. It is convenient to arrange certain affections under this head, notwithstanding it is doubtless true that every so-called functional disorder involves some structural change. Admitting this, a dis- order is to be distinguished as functional if it be non-inflammatory, and the circumstances are such as to exclude all the different varieties of structural change which morbid anatomy, in the present state of our knowledge, recog- nizes. With this definition, what are the func- tional disorders referable to the brain? The different kinds of mental derangement mania, monomania, melancholia, dementia may be considered as varieties of functional disorder of the brain. (See INSANITY.) In this statement it is implied that, in a certain sense, the normal intellectual and emotional faculties are to be regarded in the light of cerebral functions. We may assume such to bo the fact, without any skepticism as to the existence of the soul, in which consists personality, and which will sur- vive the body, albeit it is in the order of Prov- idence that in the present life the exercise of the mental faculties, and even the consciousness of being, are dependent on the physical organ- ism. The phenomena embraced under the name delirium, and the more or less complete loss of consciousness and volition called coma, are evi- dences of functional disorder of the brain oc- curring in connection with various diseases, without involving either cerebral lesions or in- flammation. These forms of functional disorder occur in fevers, and also in various local affec- tions. Under these circumstances the brain is functionally disordered in consequence of mor- bid conditions of the blood. Thus the delirium of typhus and typhoid fever is referable to those blood changes, imperfectly understood as yet, in which consists the essential pathology of these diseases ; and the coma occasioned by certain diseases of the kidneys is an effect of an accumulation of urea in the blood, or ursemia. Various remedies, by a toxical effect on the brain, may give rise to functional delirium or coma. This is true of opium, belladonna, and other narcotics, chloroform, &c. The phenom- ena of drunkenness denote functional disorder due to tlie presence of alcohol in the blood which circulates within the skull. There are certain nervous affections distinguished as func- tional, and called the neuroses, in which the functions of the brain are perverted or impair- ed ; examples are epilepsy, hysteria, hydropho- bia, and ecstasy. Finally, irrespective of all the foregoing affections, the faculties of the mind are often affected, but not sufficiently to constitute either coma, delirium, or insanity, and certain cerebral symptoms occur as results of functional disorder of the brain. Mental de- pression, irritability of temper, painful sensa- tions referable to the head, vertigo, and wake- fulness are manifestations of functional disor- der due to over-exercise or excitation of the mental powers, intellectual or emotional, pro- longed anxiety, impoverishment of the blood (anfomia), and probably by various morbid con- ditions of the latter incident to disordered assimilation, the retention of matters which should be eliminated by the different excretory organs, or the introduction of morbific princi- ples by means of the air. The relations of functional disorder of the brain to the happi- ness of individuals and the welfare of mankind