gums,

You may desire to hear some conclusions in the way of theoretical explanation. I approach this part of my subject with hesitation, and offer any hypothesis, more with a view to indicate a line of inquiry than as qualifying in any way the mutual relation of the facts. Let me then mention, what indeed you have had an opportunity of observing-first, that the margin has been found broadest and deepest in tint, and most extended as respects the number of teeth encircled, in cases where diarrhoea, or other symptoms, indicated the existence of a state of erethism of the intestinal mucous membrane; and secondly, let me remind you that in the opinion of some eminent pathologists, blood affected with tuberculosis has a peculiar affinity for oxygen. Any tendency to congestion, which may be supposed to be habitual at the reflected edge of the would probably be increased by the concurrence of intestinal irritation; and the atmosphere, if capable of modifying the condition of the blood partially stagnant in superficial vessels, might be expected to take most effect in situations most decidedly exposed to its influence. Consistently with these views the streaked gingival margin might be considered to depend essentially on tubercular depravation of the blood, and a consequent change in its relation to atmospheric influence! When the mucous membrane of the mouth is free from congestion, a greater degree of deterioration of blood may be required in order to induce the appearance under consideration; but when the circulation in this membrane is, from any cause, interrupted, the streak may be expected to occur at an earlier period in the progress of phthisis, and soon to become strongly defined. The more constant pre

sence of the symptom in men than in women, is favourable to this explanation; the habits of men, especially among the lower orders, being in various respects more calculated than those of women to induce disorder of the mucous membrane.

The question naturally occurs, whether any peculiarities of constitution or temperament tend either to prevent or to promote the formation of the margin. Such an inquiry is indeed suggested by considerations connected with the analogous phenomenon of a streak on the gums, occasioned by the absorption of lead, and which is often absent in persons who are nevertheless suffering from the introduction of that poison into the system. The want of constancy in the development of the blue line under these circumstances, may probably, however, be attributed to differences in the secretions of the mouth. There is indeed good reason for believing that considerable modifications in this respect may be referred to different degrees of care and cleanliness in the management of the teeth; but as respects the phthisical margin there are not sufficient grounds for concluding either that peculiarities of temperament increase the liability to the formation of the streak, or that varieties of habit as to cleanliness, determine its manifestation, although they may contribute to its extension. It is not improbable that characteristic markings may be discovered in the same situation in various other diseases, but materially different from the streak or border described in this communication. M. Fredericq, whose remarks* induced me to pursue this investigation, states that "a broad, dirty, livid streak * Medical Quarterly Review, for 1850, p. 539.

on the gums, opposite the lower incisors, and sometimes the upper also, is common in amenorrhoea and abdominal affections, and a white streak in the scrofulous." He is of opinion that "a somewhat narrower streak occurs in phthisis, and constitutes one of the earliest signs, often coming on about the same period as the cough, the colour of the streak being brick-red in inflammatory phthisis, but bluish in the less active form, especially in pneumonorrhagia." Some of these statements are not in perfect harmony with my own observations for as regards the margin when distinctly assuming the character which I have here described, there seems to be no evidence of its occurrence in other diseases; and I have taken some pains, in hospitals and elsewhere, with a view to ascertain whether a similar margin was present in other instances of chronic disease.

Hitherto, whenever any patient has exhibited the line clearly defined, whatever may have been the prominent complaint, a careful examination of the chest has led to the detection of phthisical disease. Let me give you an example. Among the out-patients at the Middlesex Hospital, in a woman entered as affected with dyspepsia, and in whom the streak was obvious, I found the clicking rhonchus characteristic of softened tubercle; and my friend, Dr. Alexander Stewart, being satisfied as to the existence of this sound, on referring to his notes, informed me that at an earlier period he had detected prolonged expiratory murmur in this patient, and had entertained suspicions that phthisis existed. Many similar instances have occurred to me in the course of the inquiry. You are not likely to mistake the redness of gums induced by mercury or

iodine for the phthisical mark. Independently of other circumstances, the discoloration in such cases is more widely diffused, or if it assume in any degree the appearance of a border, it does not so directly merge in the natural tint of the adjoining membrane. As respects the value of this indication in prognosis, I think you will find it a general rule that the early appearance of the streak is an unfavourable circumstance; cases in which this occurs tending to proceed more rapidly than those in which the streak is absent; whereas freedom from the streak, even in the third stage of the disease, has been particularly noticed, in those patients in whom the results of treatment have been most encouraging. Breadth of the discoloured margin, and its extension around the molar teeth, you may regard as affording unfavourable indications.

In reference to diagnosis, there is reason to believe,1st. That the absence of the streak in men affected with inconclusive symptoms of consumption may incline you to a favourable interpretation of any such suspicious indications, but that in women rather less weight is to be attributed to this negative sign.

2ndly. That the presence of the sign in women is almost conclusive evidence of the existence of the tubercular element in the blood.

When in either sex it coincides with a pulse not materially altered in frequency by change from the sitting to the standing posture, the presence of phthisis may with high probability be assumed, even before having recourse to auscultation.

The degree in which this appearance exists is not without importance in relation to treatment. When, for

instance, the margin is considerable in extent and intensity, it is often advantageous to administer refrigerant remedies, especially salines combined with prussic acid, as a preliminary to the employment of cod-liver oil, or any tonic medicines or stimulating diet; and when, as often occurs, diarrhoea accompanies this condition, trisnitrate of bismuth is specially useful. There is reason to believe that the presence of the streak, in some instances, indicates the existence of a tubercular taint in the constitution, before any signs of such a condition can be detected in the lungs. When the streak is absent, whatever be the pectoral symptoms, we have at least one ground for assuming that the constitution is not extensively involved, and we may hope to be able, by the administration of suitable remedies, to promote healthy nutrition, and avert or retard the establishment of phthisis.

When consumption exists in any individual, every structure is prone to partake of the disease, and various circumstances may modify the extent to which the lungs are affected. Even if it were practicable to replace disorganized lung with healthy tissue, yet if the blood remained deteriorated, and the processes of nutrition defective, the fatal issue, although deferred, would be equally certain; any particular which seems calculated to assist our judgment regarding the constitutional condition is therefore entitled to attention. I readily acknowledge that extended observation is required, in order to determine the qualifying circumstances to be regarded in fixing the exact value of the sign which I have now commended to your attention; and this object will be promoted by a due regard