don, met with an instance in a little girl, two years old, who lost her life from having inhaled a portion of the claw of a lobster, which was firmly fixed in the trachea, a little above the level of the upper bone of the sternum. A solid or heavy body, as a bullet, pebble, shot, or grain of corn, will, on the contrary, all other things being equal, be almost certain to pass into the bronchial tubes, in obedience simply to the laws of gravity. No contraction of the trachea, however strong or energetic, would be likely to retain it in that canal beyond a few seconds; the moment the spasm relaxes it would lose its hold, and the body would sink, by the force of its own weight, into the passage below. If a bean, pebble, or other similar substance has occasionally been found in the trachea after death, or during the operation of tracheotomy, such an event is to be regarded rather as an accidental than an ordinary occurrence. In either case, it is not, as a general rule, arrested there, but simply impelled there by the expulsive efforts of the lungs.

The disposition of the foreign substance in the bronchial tubes varies according to a number of circumstances, of which the principal are the relative capacity of these tubes, or, rather, the situation and arrangement of the septum by which they are united to each other, and the configuration, volume, and weight of the intruding body.

It seems to be well ascertained that foreign bodies, upon arriving at the inferior extremity of the trachea, have a much greater tendency to pass into the right bronchial tube than into the left. That an occurrence so frequent and so remarkable should have given rise to various conjectures as to its nature, is what might reasonably have been expected, and yet it is not a little extraordinary that, amidst so much investigation and speculation, the true cause of it should have remained so long concealed. The tendency in question was supposed by almost every one, until recently, to be owing to the difference in the diameter, length, and direction of the two tubes. As the right is shorter, wider, and more horizontal than the left, it was, perhaps, natural enough to conclude that it was particularly favorable to the entanglement of foreign substances. But there was, unfortunately, one great defect in this theory, the fact, namely, that it omitted to take cognizance of the circumstance that a foreign body, descending the trachea by virtue of the laws of gravity, would be more likely to seek an oblique than a horizontal passage. If this be true, and it can hardly be otherwise, it is obvious that the

left and not the right bronchial tube is the one into which the offending substance ought generally to fall. This, however, as has been already seen, is not the case. Some, again, have imagined that this tendency is attributable to the greater capacity of the right lung, in consequence of which the air habitually enters the corresponding canal with proportionably greater force and velocity, thereby impelling the intruder in the same direction. Finally, a third class of writers have endeavored to account for it by the circumstance of the right tube forming a more obtuse angle with the trachea than its fellow of the opposite side.

The above explanations are certainly ingenious, but they all labor under the disadvantage of being insufficient for the purposes for which they have been invented. The true cause, undoubtedly, is the peculiar position and arrangement of the septum (Fig. 1) at

Trachea and bronchial tubes, laid open in front. 1. Trachea. 2. Right bronchial tube. 3. Left bronchial tube. 4. Bronchial septum, somewhat magnified, to render it more conspicuous.

the root of the trachea, indicating the line of junction of the two bronchial tubes. This septum, spur, or ridge, to which, from its situation, the term bronchial may be appropriately applied, is not,

as will be seen hereafter, in the mesian plane, but decidedly to the left of it, as may be shown by a perpendicular line extending from the centre of the rima of the glottis to the corresponding point of the inferior extremity of the windpipe, properly so called. Hence a body, especially one of considerable bulk, after having passed the larynx, will be very likely, by striking this septum, as it will be apt to do in its descent, to be pushed over towards the right side, its entrance into the corresponding tube being still further favored by the greater diameter of this tube. The probability, indeed, is that both these circumstances co-operate in promoting this result, so interesting and important both in a diagnostic and practical point of view. Mr. Goodall, of Dublin, appears to be entitled to the credit of having first called the attention of the profession to the part played by this septum in directing the passage of foreign substances in their descent towards the lungs. The observation is unquestionably one of great value.1

Sometimes each bronchial tube contains a foreign body simultaneously, as in the interesting instance observed by Professor Mott. In this case, which proved fatal after tracheotomy had been performed, a piece of the kernel of a walnut was found impacted in each canal.2

Occasionally, again, the foreign body descends beyond the bronchial tubes, into one of their principal divisions. Thus, in a case observed by Dr. J. G. Forbes,3 of London, it was lodged in the orifice of the third branch of the canal communicating with the middle lobe of the right lung. Such an occurrence is, of course, very rare, and can happen only when the substance is unusually small, as in the present instance.

When a foreign body is retained permanently, or for any considerable period, it either becomes encysted, and is thus rendered comparatively innocuous; or, as more generally happens, it sets up irritation in the circumjacent parts, which in one case, perhaps, prepares the way for its own expulsion, while in another it may produce such ravages as to destroy the patient. The structural changes liable to be induced by its presence, will claim due consideration under the head of pathological effects, in another part of this volume.

1 Stokes's Treatise on the Diseases of the Chest, p. 239, Philadelphia, 1844.

2 Cooper's Surgical Dictionary, Reese's Appendix, art. Tracheotomy.

3 Medico-Chirurgical Transactions of London, vol. xxxiii. p. 14, 1850.

It has been stated by Dr. John Browne,' of Dublin, that the impaction of foreign bodies in the bronchial tubes is of less frequent occurrence in children than in adults; and he appears to think it fortunate that it should be so, as the narrowness of the glottis, the smaller size of the trachea, and the greater sensibility of the organs generally in young subjects render such accidents peculiarly severe. It is to be regretted that this gentleman has not furnished us with his reasons for this opinion, for which, I think, there is certainly not the slightest foundation in truth. So far from this being the case, I should suppose that just the reverse would usually obtain. I am not aware that children generally inhale smaller bodies, absolutely speaking, than adults; and if this is really the fact, and there can be no doubt of it, we may legitimately infer that the impaction of these substances will be much more likely to take place in young than in old subjects, because of the greater size of the caliber of the respiratory passages in the latter than in the former. Let us, for example, take a bean, half an inch long by the third of an inch in diameter; such a body would readily pass the glottis, and descend into one of the bronchial tubes, where, from its large bulk, it would almost inevitably become fixed. In the bronchia of an adult, on the other hand, it would be comparatively small, and, therefore, have a tendency to remain loose, if not to play up and down the windpipe.

I am not aware that the statement of Dr. Browne has been corroborated by other observers, and I have alluded to it here merely because of its practical bearing. The impaction of a foreign substance in the air-passages is at all times a most serious occurrence, and nowhere certainly is it more so than in the bronchial tubes, where it is always extremely difficult to reach and seize any body, whatever may be its volume or form, with any instrument, however carefully constructed, or however dexterously managed.

The question as to the relative frequency of the situation of foreign bodies in different portions of the air-passages is one of great practical moment, and it is not surprising, therefore, that it should often be a source of anxious inquiry. Desirous of throwing as much light upon this subject as my limited opportunities will admit of, I have taken special pains to examine the numerous cases analyzed in this report, and the following are the results:

Edinb. Med. and Surg. Journal, vol. xxxv. p. 286.

The number of cases of death, without operation and without expulsion of the offending body, is twenty-one. In these the substance was situated, in eleven, in the right bronchial tube; in four, in the larynx; in three, in the trachea; in one, partly in the trachea and partly in the larynx; in one, in the "lung;" and in one in the right thoracic cavity. In not a single instance did it occupy the left bronchial tube.

In thirty-four cases, subjected to operation, or general treatment, the extraneous substance was situated twice positively, and eleven times probably, in the right bronchial tube; four times certainly, and four times probably, in the left bronchial tube; seven times positively in the trachea, and fourteen times positively in the larynx. In two of the above cases a careful examination of the chest, during life, rendered it evident that the foreign substance, although found in the left bronchial tube after death, occupied the right tube of that name during the greater portion of the time which intervened between that event and the occurrence of the accident.

It will thus be perceived that the prevalent opinion that foreign substances are more frequently situated in the right bronchial tube than in the left is not imaginary, but well-founded. The difference, indeed, is most striking, and well worthy of remembrance, both in a pathological and practical point of view. It will be seen that the larynx is also a frequent seat of extraneous substances; but this circumstance is apparent rather than real, and depends upon the fact that the offending bodies, when impacted here, are more easily detected and extracted than when they are lodged in the trachea and bronchial tubes. Our knowledge does not enable us to state, with any degree of certainty, how often, relatively speaking, extraneous substances, when situated in the larynx, occupy the ventricles of that tube. The probability is that they do so in a little more than half the number of cases.

SECTION IV.

ENTRANCE OF FOREIGN BODIES.

The glottis, although by far the most common, is not the only avenue by which foreign bodies may reach the windpipe; occa