in a fluid which normally contains no cellular elements indicates disease of the central nervous system. In general paralysis, syphilis of the nervous system and tabes dorsalis even in early stages of these diseases, the deposit is seen to consist almost entirely of lymphocytes. Some evidence of the progress of the disease and the effect of treatment may be obtained by counting the number of cells at different periods. In tubercular meningitis there are also lymphocytes in abundance although usually tubercle bacilli cannot readily be found, yet bacilli are present, for injection of the fluid into a guinea pig is a certain means of determining whether it is tubercular meningitis or not; for if it is, the animal is sure to develop tubercle. In epidemic cerebro-spinal meningitis the cells in the deposit are polymorphonuclear leucocytes, and in the leucocytes can be seen the specific organism Diplococcus intracellularis with its characteristic staining and cultural characters. Septic, pneumonic and pyogenic organisms may also invade the central nervous system giving rise to meningitis, and in these cases the deposit will be polymorpho-nuclear leucocytes, and perhaps the specific organisms may be seen in stained preparations; but if not, they can be obtained by cultural methods. In all operations of this kind antiseptic precautions must be adopted both for the safety of the patient and the reliability of the findings, otherwise organisms in the skin may contaminate the fluid withdrawn.
Other formed elements which may be found are large cells, macrophages containing blood pigment; these cells indicate that some haemorrhage has occurred. One of the most important uses of lumbar puncture has been the discovery of the cause of sleeping sickness. The fluid withdrawn and centrifuged contains, as one would expect from the lesions in the brain and spinal cord, large numbers of lymphocytes and plasma cells (see Plate II. fig. 10), but besides, the actively moving organisms (Trypanosoma gambiense) (see Plate II. fig. 1) which are the essential cause of the disease. It has been remarked that the normal cerebro-spinal fluid is devoid of proteins, but in the various forms of disease above described as containing cells in the centrifuged deposit, there is also in the fluid an appreciable amount of proteins. If pathological cerebro-spinal fluid be added to an equal quantity of saturated solution of sodium sulphate there will be a distinct turbidity indicating the presence of proteins in appreciable quantity. This appreciable quantity. of proteins is especially significant in the case of fluid withdrawn from cases of general paralysis or tabes, for it goes pari passu in amount with a reaction which is known as the Wassermann sero-diagnostic reaction for syphilis; a reaction, however, which is too complicated to explain here, but which is of the greatest importance for the diagnosis of general paralysis and tabes dorsalis. The finding of the Trypanosoma gambiense in the cerebro-spinal fluid in sleeping sickness led to the belief that the specific organism of syphilis, Spirochoete pallidum might be found in the cerebro-spinal fluid in syphilitic diseases of the nervous system, but although in a few instances successful inoculation of animals with syphilis by injection of the cerebro-spinal fluid has been effected, yet the organism has only once been found in the fluid withdrawn by lumbar puncture. It has long been a puzzle why only certain individuals, about 5%-8% of those infected with syphilis, should subsequently suffer with diseases of the nervous system. The skin and mucous orifices are the most common sites of secondary and tertiary lesions and after this the nervous system, but no tissue or structure in the body is exempt. It is probable that the virus attacks tissues when in a low state of resistance in a random metastatic manner. It is necessary to distinguish between these true syphilitic lesions which are the result of the reaction of the tissues to the living virus and the parasyphilitic affections, which own a different cause. The former may be most successfully treated with mercury, which has the power of devitalizing the specific virus and preventing its multiplication, the same as atoxyl prevents the multiplication of the trypanosomes. Iodide of potassium favours the absorption of the degenerative products of the cells, and syphilitic tumours may rapidly resolve and disappear under the influence of these drugs. Nervous symptoms even so severe as to threaten a rapidly fatal termination may disappear with energetic treatment when they are due to the syphilitic virus producing an inflammatory reaction of the tissues; not so, however, when the symptoms are slow, insidious and progressive, due to a primary decay of the neurones, e.g. the parasyphilitic affections tabes dorsalis and general paralysis of the insane, which are really one and the same disease owning the same cause. We can understand that it may be a chance whether a man suffers with true brain or spinal cord syphilis, because it may be a chance whether the virus is carried there by the blood-vessels and lymphatics, and if carried there finds a suitable nidus to develop. But the parasyphilitic affections appear to be due to a premature primary decay of the neural elements owing to bio-chemical changes in the body induced by reaction to the syphilitic virus. There are a good many facts now forthcoming which show that the subjects of parasyphilis present mild symptoms of syphilis, and upon an average it is not until ten years later that they develop nervous symptoms, which are aggravated rather than benefited by mercury. Such subjects are immune to a second attack of syphilis, and the examination of the blood and cerebro-spinal fluid by the Wassermann reaction of the deviation of the Complement reveals the fact that there is a bio-chemical change; the presence of this reaction may be correlated with the fact that these fluids contain lipoid substances and a globulin in excess. The cerebro-spinal fluid contains these lipoid substances and globulin in proportion to the degree of decay of the neural structure; they arise from the destructive metabolism of the neural elements. But the same lipoid substances and globulin are found only in the blood of syphilitic individuals, consequently it must be supposed that in general paralysis and tabes certain groups and systems of neurones undergo decay from excessive metabolic activity which is brought about by two factors (1) a bio-chemical stimulus, the syphilitic poison, (2) excessive physiological stress, which in non-syphilitic individuals would only lead to cerebral or spinal neurasthenia.
Sleeping Sickness is characterized by a progressive lethargy, paresis, tremors and the signs and symptoms of neural exhaustion without neural destruction; it comes on slowly and insidiously often years after infection and eventually terminates fatally by intercurrent disease or paralysis of the bulbar centres. Examination of the central nervous system explains the fatal lethargy; the perivascular and meningeal, lymphatics are filled with lymphocytes and plasma cells (Plate II. fig. 6.); moreover, the neuroglia supporting cells have undergone a rapid formative proliferation (Plate II. figs. 3 and 5). The effect of this morbid process is to deprive the neural elements of oxygen and nutrition; the neurones in consequence, although not destroyed, are nevertheless unable to function for more than a brief period.
(γ) Poisons introduced into the Body.—The most widespread and potent cause of nervous and mental disease is the abuse of alcoholic stimulants. At least 20% of the inmates of the asylums of London are admitted with a history of alcoholism. In not more than 10% is alcohol the efficient cause of the mental disease; in many it is only a contributory factor, and in not a few the lapse from moderation to intemperance is the first sign of the mental breakdown. Most of the patients admitted inherit the neuropathic tendency, and it is a rare thing, among such, to find cirrhosis of the liver with ascites, condition which indicates long persistent spirit-drinking. The writer, from a very large experience as pathologist to the asylums of London, only remembers one such case, and that was in a notorious woman who was convicted nearly four hundred times for drunkenness before she could be certified as of unsound mind, a fact which indicates that she inherited a very stable nervous constitution. To people with unstable nervous systems a relatively small quantity of alcohol may act as a poison. Thus epileptics, imbeciles, criminals, potential lunatics, hysterics, neurasthenics and the subjects of head injury are liable to become anti-social and dangerous to themselves and others by indulgence in quantities of alcohol which would have no harmful effect upon the mentally stable and sound individual. Alcohol may produce acute delirium, with fine tremors, and, generally, visual hallucinations of a horrible nature, indicating acute toxic influence upon the brain. This apparently acute form of alcohol poisoning is met with in chronic inebriates especially; it is much commoner in men than in women, and it is remarkable how a severe injury or illness, such as pneumonia, will bring out delirium tremens in a drunkard. Chronic alcoholism manifests itself in a variety of ways according to the inborn temperament of the individual. The well-fed man with an inborn stable well-balanced mental organization is able to consume daily large quantities of alcohol with no other obvious effect than the lowered moral sense of indulgence in a vicious habit. However, chronic alcoholics form a large proportion of those convicted for crimes of violence, homicide, suicide and sexual offences. Alcohol acts especially upon the higher centres of the brain, and a drunken man may exhibit “the abstract and brief chronicle of insanity, going through its successive phases in a short period of time” (Maudsley). The effect on the nervous system of chronic tippling may be dementia, a very characteristic manifestation of the mental degradation being absence of knowledge of time and place, personal illusions and loss of memory of recent events, indicating a failure of receptivity and of the formation of memory-pictures in the higher centres, mental confusion, delusions of persecution, and especially a morbid jealousy with suspicions of fidelity of the husband by the wife or of the wife by the husband. A certain amount of improvement may occur when total abstinence is enforced, which shows the poison has damaged but not destroyed the nervous elements. There is also a form of mental disease characterized especially by hallucinations of hearing and vision, associated with delusions usually of a persecuting nature, unaccompanied by other marked mental disorder. Abstinence and proper control generally ends in recovery, but such cases so frequently relapse that it is fairly certain that alcohol is an exciting factor to a morbid or insane temperament. Besides mental symptoms of chronic alcoholic poisoning, there is frequently paralysis, affecting especially the lower limbs (structures suffer most where vitality is least), although the upper limbs, and even the respiratory muscles, may be affected in severe cases. The patient, usually of the female sex, becomes helpless and bedridden, and death frequently occurs from heart failure. Characteristic features of this affection are great tenderness on pressure of the muscles, especially of the calves, absence of reflexes, a variable degree of skin anaesthesia, wasting of muscles and alteration of the normal electrical reactions, and frequently pyrexia. There is no loss of control over the bladder and bowels, unless there is very marked dementia. This “complex of symptoms” points to a peripheral polyneuritis, although frequently changes occur also in the ganglion cells, from which the axis cylinders of the nerves have their
