ESSAYS ON GENERAL PATHOLOGY
To resume the subject of morbid associations, we shall, in the next place, consider in what manner the secerning process suffers in combination with other conditions of disease. The proper separation of the several constituents of the blood, contained in the different secretions, especially in those of the more perfect or complicated kind, requires a healthy state of the bloodvessels. Acute inflammation is well known to be attended with diminution or arrest of the proper secretions of the part
... n which it occurs. It may be easily conceived to disturb the affinities of the blood, and by changing its quality and embarrassing its course, to derange a process which is dependent on a nice adjustment of the whole. In many instances, where inflammation exists in a subdued degree, it seems to give rise to an augmented separation of fluid, and it is common to say that the secretions are increased by it. It will be found, however, in these cases, that the character of the fluid is changed in proportion to its increase, and that the real process of separation is more or less impeded, and always deranged. Besides, in a majority of instances, where the discharge is augmented,the fluid separated becomes of awaterv nature, and cannot be said to rank with the more perfect or elaborate secretions. The process is one better named transudation than secretion; and it will be evident, on consideration, that the aqueous matter is given off from the congested vessels which surround or blend with the inflammation, rather than from those more intimately concerned. Inflammation, therefore, may be . said to arrest secretion, and prevent the proper separation of those constituents which should be removed from the blood. It is rather to congestion than to inflammation that we are to ascribe those increased discharges of fluid which often go by the name of inflammatory secretions. It is true that inflammation is often more or less associated with increased discharges, but what we have said of the change in the nature of the secretions is always s to be remembered. The quantity cannot be very greatly altered without a change of quality. Instances of increased discharges, separated from the emunctorial surf'aces, when under the influence of congestion, will readily occur to every one. In many cases of diarrhœa, especially where it supervenes on a dropsical affection, a gorged state of the mesenteric vessels seems to be its immediate occasion. The same is true of many profuse and vitiated secretions from the bronchial membrane, which take their origin in the congestion dependent on cardiac disease. Leucorrhoea is greatly favonred by all occasions of uterine repletion, and the employment of such means as are useful in obviating congestion .is acknowledged as useful in the treatment of this complaint. Important changes in the composition of the secretions are sometimes connected with states of disordered nutrition, inasmuch .as the organs engaged in the office of secretion may suffer structural changes which prevent the due formation or separation of the discharge. These organic changes are themselves frequently associated with inflammation. The alteration in the urine which characterizes the cachectic inflammation of the kidney, described by Dr. Bright, affords us a good example of the combination of morbid nutrition and secretion. It would seem, that whilst the surrounding texture is consolidated, the uriniferous tubes, in place of the natural secretions, become gorged with bloody and albuminous particles. Some hepatic diseases, in like manner, destroy the secreting surface from which the bile is destined to be removed; but it appears that considerable disorganization of the liver may proceed without so great a change in the quality of the bile as might be expected & a g r a v e ; priori. A disordered or diminished secretion is not only an effect, but frequently becomes a cause, of unnatural accumulations of blood; just as we find in respect to other conditions of disease, the antecedent becomes sometimes the consequent; and this must ' , necessarily be so, from the nature of the dependency. Besides the various uses which the different secretions are intended to perform, they have a secondarv but important office in equalizing the circulation of the blood. Some of the secretions of the body appear to act like safety-valves in relieving the gorged vessels in the neighbourhood ; of these, the removal of perspiration from the skin, and of the urine from the kidneys, are, perhaps, the most striking and important. If the removal of the accustomed secretions be impeded, an inordinate fulness or congestion takes place, and this would exist to a greater extent were it not for the reciprocal relation which is maintained between the quantity of fluid which is separated by those organs which have an affinity in their functions. Thus we are well aware, that when the surface of the body is cold, the kidneys are principally active in removing the watery matter from the blood, and that the skin secretes most abundantly when the kidneys are least in requisition. These secretions, therefore, to a certain extent, tend to restore the equilibrium of the circulation. 'As an illustration-of congestion originating in diminished secretion, we may refer to the disorders of the menstrual functions..A deficiency of the catamenial discharge is a common cause of vascular repletion in the uterine system. It is probable that many of those diseases to which the uterus is obnoxious at a certain period of life, are immediately preceded and favoured by a state of congestion, arising from the cessation of the menstrual discharge ; but it would be absurd to suppose this the only state necessary for the production of all such disorders. When it is said that organic changes arise from functional derangement, I conceive it must be meant that they are, in some way, associated with imperfect secretions and chronic congestion. Amenorrhoea is well known to be accompanied with many disorders which are, perhaps properly, attributed to congestions dependent on the impoverished secretion. I remember a case of extraordinarily enlarged mammae which was very greatly bene--nted, if not entirely remedied, by attention to the menstrual secretion. I believe Sir Astley Cooper, in his work on the Diseases of the Breast, mentions similar instances which were successfully treated upon the same principle. The vicarious discharges of blood which occasionally attend a suppression of the ! catamenial functions, must, in like manner, be allowed to be produced through the mediation of congestion ; and many of those . hysteric affections and anomalous sensations which also attend such derangement, it is common to consider as ascribable to local . plethora. Disorders of secretion sometimes actually give rise to inflammation. The congestions which we have mentioned pass into inflammatory complaints by insensible degrees. In some-instances, the sudden arrest of morbid secretion is immediately productive of inflammation. The cessation of chronic purulent discharges is commonly regarded with dread, but in many. of these instances it is probable that the disappearance of the secretion is a consequence, rather than a cause, of the fresh accession of disease. In those cases where otorrhcea seems to pass into meningitis, it is not in every case clear whether the diminution of the morbid secretion be in the relation of cause or effect. There is still another way, which may be just alluded to, in which diminished secretion may be a source of mischief. Inflammation may be dependent on a want of that natural defence which a secretion is intended to afford, or be in some degree connected with the retention of that matter in the blood which it was designed to separate. Of the latter method we shall speak on another occasion. The inflammation of the eyeball which follows a section of the fifth pair of nerves, seems to be not so much dependent immediately on the injury of the nerves, as on the alterations of the secretions which serve as a defence from the irritation of foreign matter. " This conjecture," says Dr. Alison, " is supported by the fact, that inflammation of mucous membranes, and, among others, of the tunica conjunctiva of the eye, is observed in other cases where there is great debility of the circulation, deficient secretion, and insensibility, as in animals kept long fasting, and in the last stage of fever."* Somewhat in the same manner that inflammation produces a local derangement in the secretory functions, a state of general febrile disturbance is accompanied with a common disorder of the secretions of the body. The skin becomes parched and hot, the urine sparing and high coloured, and the tongue and fauces more or less dry or clammy. In these cases, the derangement of the secerning process, and that of the arterial system, may acknowledge a common cause in a disturbance of the nervous centres; but it is probable that something may also be due to other influences of a more mechanical or appreciable nature. A change in the speed of the circulation, and the tension to which the vessels are subjected, may, in themselves, be conceived to be productive of an embarrassment in the secretory functions. -The facility with which the secretions are produced must certainly influence their composition, and a scanty separation must be for the most part a disordered one. A moderate degree of excitement is not necessarily attended with any disturbance of this kind, but if the acceleration be considerable, it seems greatly to interfere with its healthy regulation. It must be acknowledged, that in most febrile cases, a multiplicity of other derangements must also be concerned in vitiating the process of secretion, but each may be allowed to claim a separate attention. Again, a disturbance of the secretory function must itself react on the * Outlines of Pathology, p. 116. 1636.