the will in consequence rendered of no value. Dr. Monin concludes his interesting article by directing attention to senile mental troubles in general. He recalled the fact that the brain, the organ by which so many aged persons succumb is, as has been often remarked, under the close dependence of the digestive tube. Consequently, the resources of hygiene and of curative medicine should be applied to the gastro-intestinal sufferings of the aged. For it is beyond doubt that melancholic ideas and insanity start, as frequently perhaps as apoplexy (in aged persons) from this gastric vital center, so justly surnamed by Bichat the "abdominal brain."

In connection with the subject of insanity I may here reproduce a note from the Journal de la Sante, by which we are informed that Dr. Giacchi, of Turin, in writing on the manner in which lunatics die, observes that often lunatics present in the later periods of their unhappy existence a surprising metamorphosis. A notable number of acute or chronic lunatics, and even demented subjects, who for some years have been incapable of reasoning correctly, miraculously recover on their death beds full consciousness of themselves. They die conscious, and often placidly and serenely, as much and even more so than persons of sound mind who succumb to the same malady. Often, in the few days which precede death, one finds in the one as well as in the other (sane and insane persons) a complete interversion, particularly when life is extinguished by the aggravation of chronic maladies of the abdomen or of the chest. Thus, while the phthisical subject or patient affected with chronic diarrhea at its last stage is often in a state of mental aberration, or at least of weakness of the intelligence; on the contrary the lunatic, under the influence of the last stages of physical disease, sees the darkness of his intelligence dissipated; similar to the flame which is about being extinguished, the mind resumes it lucidity, a striking contrast with the darkness or agitation of insanity.

PARIS, April, 1890.

A LATERITIOUS DEPOSIT-Knocked down by a brickbat.-[ORIGINAL.]

Abstracts and Selections.

SOME MOOT POINTS IN OBSTETRICS — (D. T. Smith, M. D., Louisville, Ky.) For more than twenty centuries large numbers of the foremost minds in the ranks of medicine in each succeeding age have directed their ingenuity and learning to the explanation of the phenomena of labor. To assert, then, that a very large proportion of the explanations hitherto offered of the movements involved in the mechanism of labor are wholly erroneous, would appear to deserve the charge of presumption and arrogance.

However positive I may feel, therefore, in my convictions, I will begin by deferentially asserting that facts, principles, and analogies can be adduced strongly leading to the conclusion that much of the accepted teaching relating to the factors and mechanism of labor is

erroneous.

These errors refer

1. To the uses of the amnion.

2. To the cause of head presentation. 3. To the cause of rotation.

4. To the mechanism of extension.

1. The Uses of the Amnion. The uses commonly ascribed to the amnion in our physiologies are such as might be inferred from observations of its office in the higher animals, and especially the human race. The amniotic fluid is said to preserve the fetus, and also the fetal membranes, from mechanical injuries; to permit the limbs to move freely and protect them from growing together; and also to aid in dilating the os uteri during labor. This no one can gainsay, as far as the higher animals are concerned; but if we inquire the office of the amnion in the reptile, the batrachian, or the bird, will this answer suffice or apply? Certainly not. So far as we know, the different amnion, do not grow together with any more parts of the body of the eel, which has no frequency than those of the snake or the crocodile, which have an amnion. Nor is it likely even, with the bird, that the fluid of the amnion one time in a million protects the young from injury. Nor could it aid, in any of these animals, in opening the mouth of the uterus. What, then, can be its office in the lowest animals in which it occurs, and the office common to them and the higher animals? But one appears. It is that of a waste-bag for the injurious excretions from the body of the fetus.

In the very lowest vertebrates the umbilical vesicle, or yolk-sac, was sufficient to preserve, in a proper condition, the nutrient material of the ovum. But a little higher up the yolk-sac

had to be supplemented by a receptacle for material likely to contaminate this store of food; and this receptacle nature converted, among the higher animals, into a protection for the embryo and an aid in parturition. From this view of the case, one might conclude that the amnion, as a waste-bag, is of more importance to animals low down in the scale than to the higher animals, in whom the waste is carried off in part by the placenta.

It is unnec

2. Cause of Head Presentation. essary to repeat the various theories that have been put forth from time to time as to the cause of head presentation; it is enough to say that no one of them is accorded general acceptation among obstetricians. I will simply state my own view and the manner in which it seems borne out by facts and analogies.

Whoever has practiced diving in deep water has discovered that if he holds his arms in such a way as not to hinder his progress— folded at his back or breast, for instance, or pressed to his side-and then kicks out with his feet, he will go directly and head foremost to the bottom. Now, the position of the child in the uterus and the course of its development are such that it makes essentially similar movements. The flaccid state of the walls of the uterus allows them to yield when pressed against by the lower limbs, and in this way the fetus gains the advantage that would accrue to it from swimming in a larger mass of water than that actually contained in the uterus.

If now we add to the influence of these movements that of the increasing conicity of the lower segment of the uterus that develops during the latter months of pregnancy, we can easily account for the greater preponderance of head presentations. In every position the mother takes, except that of lying on the side, the outlet of the uterus is lower than the fundus, and in all except the latter the movements the child spontaneously makes will tend to place it head downward.

As the lower segment becomes more and more conical, the head is the more likely to remain in it when once placed there, since the arms of the fetus are passive, and the activity of the legs continues, and even increases, as gestation advances.

On the other hand, should the breech get into the lower segment, the extension of the legs will broaden the corresponding extremity of the fetal ovoid giving it a tendency to escape and make place for the head.

In the early months head presentations will more often fail, for the reason that the fetus will move more sluggishly and more rarely place its head downward, and for the further reason that, the uterus being spherical, the

fetus will fall over more readily, even after it has gained the inverted position.

The large size of the head of the hydrocephalous infant will prevent engagement in the conical segment, and, furthermore, the movements of such infants will be less energetic and less persistent.

Dead fetuses will be likely to remain in the position in which death found them, and so present at birth. In a very few instances decomposition might generate gases in the lungs alone, and thus determine breech presentation by causing the head to rise. An extensive generation of gases, on the other hand, would probably leave the head least affected, and this would naturally settle to the lowest point.

It is greatly in favor of this theory that it supplies a reason for the equally predominating frequency of head presentations in quadruped mammalia, which no other theory has ever done. A calf, a pig, or a colt, or the young of any other quadruped mammal, if thrown into water the moment after birth, in such a way as to be plunged beneath the surface, will, by the exercise of natural walking movements, swim to the surface. Now, the outlet of the uterus of the quadruped mammal is higher than the fundus in nearly every position the animal ordinarily assumes. By the exercise, therefore, of its natural walking movements, the young of the quadruped mammal carries itself head foremost upward to the outlet, resulting in presentation, with great uniformity, by the head.

3. Internal Rotation. It could not be wide of the mark to say that the most important thing for the obstetrician, in the exercise of his office, to understand is the state and course of internal rotation. Rather let it be said that he who does not understand rotation in its practical bearings is not an obstetrician. This can not be said, however, of rotation in its theoretical aspects, for here there is any thing but a consensus of opinion."

It is needless to enter into details of the various theories, and of the arguments adduced to sustain them on the one hand or to refute them on the other. They are found in all the text-books of obstetrics, and every student is familiar with them. I will add but one objection, and that to a theory proposed, I believe, by Berry Hart. This theory is that the part of the presenting extremity of the fetal ovoid that first reaches the floor of the pelvis is directed forward. I think this theory erroneous in principle and refractory to experimental proof. To illustrate what might be supposed to take place under the circumstances named, let a boot-tree be taken and suspended on a rod passed through a hole bored through

the longitudinal axis of the leg in such a way that it can revolve without hindrance. Now let the boot-tree be moved forward by a force applied to this rod, and at the same time let the toe be permitted to press on the floor. Will the toe turn forward in such a case, or will it not? Most assuredly it will have a tendency to turn to the rear. And just as little, in my opinion, will the part of the fetal ovoid that first touches the floor of the pelvis turn forward merely by reason of being the first part that does so touch.

The principle I would propose as explaining rotation is the almost axiomatic one that a force moves along the line of least resistance; or, rather, that a force will be deflected from points of greater resistance.

My assumption is that the anterior surface of the passage is the line of greater resistance, and that the roughest and most resisting surface of the presenting part of the fetal ovoid will be forced from the anterior to the less resisting posterior surface of the passage.

To make clearer the physical principles involved in rotation, let us take a tube of wax constructed of parts of two other tubes, one larger than the other. Into this tube let a cylinder be inserted with a bullet attached to one side of the advancing end, in such a way as to compel the cutting of a groove in the wax as the cylinder advances, and let the beginning of the groove be at a point in the part of the tube formed by the segment of the larger circle. It is clear that the wall of the groove thus made which is on the side next to the larger extremity will be higher and stronger than that on the side toward the smaller extremity, just as a furrow made by a plow driven along a hillside will be deeper on the upper than on the lower side. The bullet will, therefore, necessarily move toward the segment of the tube corresponding to the smaller circle, carrying the cylinder with it, until a point has been reached by the bullet where the two walls of the groove it makes in the wax shall be equal in depth, when rotation will cease.

Let us now apply this test to the several presentations and positions. In vertex presentations with the occiput anterior, and in rotation of the shoulders and hips, the movement is explained equally well by ascribing it to the influence of the smooth ischial planes. And although it is obvious that the two opposite surfaces of the ovoid in the two last-named instances are not different in smoothness, nevertheless here, as in occipito-anterior positions, the movement is in the direction of least resistance.

But in occipito-posterior positions, in face

presentations, and in rotation of the head in breech presentations, we have a clear field for the application of the principle. Let us take up, first, rotation in occipito-posterior positions. Here we have, on one side of the presenting extremity of the fetal ovoid, the roughnessness of the angles of the forehead, the nose, chin, and malar bones; and, besides, the face, being free of hair, may be stripped of the vernix and thus become more resisting. On the opposite side is the smooth occiput, regular in outline and usually covered with hair, enabling it to retain the unctuous vernix, making it altogether favorable for gliding. The face is the rougher surface, and the occiput the smoother and less resisting.

According to the principle of physics assumed at the outset, the surface first described, the face of the fetus, will be driven with the greater force from the point of greater resistance, and will turn to and follow the line of least resistance. The part with the smoother surface, the occiput, on the other hand, while it will geek also the line of least resistance, will be compelled by the more resisting anterior part to turn to and pass out by the line of greater resistance.

Now, which of the surfaces of the passages affords these lines of greatest and least resistance respectively? If we examine the pelvis, we find that the passage presents a short curve under the pubes and a long curve along the sacrum. Moreover, while the hollow of the sacrum is approached by a guide of bony substance, the pubes is approached over a muscular floor which may be pushed forward by the head of the child, leaving in the abrupt edge of the pubes a strong obstacle to progress. On transverse section, also, the anterior walls of the canal form part of a larger circle than the posterior walls.

If these assumptions were known to be true, it could be predicted with the greatest confidence that the face would turn back ward and the occiput forward, even if no ob-ervations had ever been made. Nor is it difficult to explain how, in certain cases, failure may occur in rotation.

Thus, if the head should reach the floor in a state of extension, the obstacles to rotation might be greater than to birth in that position; for then a wedge would have to be rotated instead of the truncated cone which is offered in case of complete flexion. Or the rigidness of the soft parts, or the large size of the head relative to that of the passages, might be so great as to make the obstacles to advance less than those to rotation, when the child would be born in the occipito posterior position.

Let us next take rotation of the head in case

of footling presentations. Here exactly the same forces operate, only they operate in some respects with greater intensity, since the friction produced by the face passing chin foremost will be somewhat greater than that produced as it passes forehead foremost. On the other hand, the passages, having been already dilated by the body of the fetus, may offer slightly less resistance to the advance of the head. But, taken altogether, the forces operating will turn the face to the sacrum with somewhat greater certainty than in vertex presentations.

If, however, extension of the head should take place during descent, throwing the face upward and the occiput backward, the chin being nearly in a line with the sternum, the point of greatest friction will be shifted to the spinal surface of the fetus, and rotation will take place so as to turn the chin to the pubes.

4. Face Presentations. In face presentations, the occiput being borne well back on the spinal column, the posterior surface of the presenting extremity of the fetal ovoid will be the most resisting. The consequence is that rotation of the forehead takes place posteriorly, and the chin is turned to the pubes. If, however, ex

LEG BROUGHT DOWN IN TRUNK PRESENTATION.

In conclusion, let us concede that not one of these deductions is true, that they are all a mere bundle of fancies; they still offer a most. valuable basis for remembering and predicting the rotation proper in each particular case. The principle may be formulated as follows: Whichever part of the presenting extremity of the fetal ovoul offers the most resistin surface will turn by the shortest route to the hollow of the sacrum. This would have to be slightly modified to apply to the after coming head, since this. would not be the presenting extremity.

In those cases of trunk presentation, also, in which it is possible for labor to proceed, the head invariably turns forward and rests above the pubes, the anterior should r becoming at the same time fixed under the symphysis. Such cases present a verbal exception to the aphorism just laid down, in that the rotation of the roughest part takes place forward and not backward. However, it is easily enough explained on the same principle of unequal friction, if we reflect that here rotation takes place above the pubes, and that the part of the canal along the lax abdominal wall, and not that along the sacrum, affords the line. of least resistance. The head, therefore,

which is here the most resisting part of the advancing fetus, turns to the wall of the abdomen above the pubes. Contrary to the teachings, it is the head then that, by its rotations, brings the shoulder under the pubes, instead of the shoulder bringing the head to the front above it.

TRUNK PRESENTATION.

Whence comes, then, the prevalent notion that the floor of the pelvis is an active power in effecting rotation? Does the pelvic floor, indeed, contribute nothing to this result? On the contrary, it contributes much, but not in the way that has been suggested. If the parturient canal were straight and continuous, the helix of the thread of the screw cut by the passing of the rough points on the presenting parts of the fetus would be very low; the fetus must needs traverse a great length of canal to cut a thread amounting to as much even as the quadrant of a circle. But with the aid of the resistance of the pelvic floor, which yields slowly and gradually before the advancing head, the helix may rise to the highest possible limit, and rotation may take place to the required degree during a very limited amount of direct advance.

On the other hand, if the pelvic floor were rigid as a board, so that advance could not take place, rotation must fail.

The observation so often made and so strenuously insisted upon by Berry Hart, that the first part of the presenting ovoid that reaches the pelvis is turned forward, is delusive only in respect of the deductions sought to be made from it. The fact is well established. But the meaning of it is that the part of the ovoid that first impinges on the floor of the pelvis becomes the pivot on which rotation takes place. When the vertex forms this pivot, the

face becomes the long arm of a lever of which the occiput is the short arm. As this pivot, then, is driven toward the pubes, the thickness of the anterior walls of the grooves cut by the inequalities of the face already described becomes more and more marked, and more and more promotes rotation.

This may be easily demonstrated by putting a floor of card-board in the skeleton of the pelvis, or taking any other circle, and while using one arm of a pair of compasses as the pivot, let the other be turned as the pivot is made to advance toward the pubes, or to a point on the circumference of the circle corresponding to the symphysis.

Thus, let b (Fig. IV) represent a ring formed by cutting a transverse section from the end of a cylindrical tube. Let now a rod be passed perpendicularly through the axis of this ring at a, with an arm c extending to the wall b, and cutting a groove into its substance. Obviously the groove so cut, the arm being symmetrical, will have each of its walls equal in depth. Now let the pivotal rod be advanced to a', and turn it until the arm c will cut a groove at the intersection of the arc b' and b. This groove will have its anterior wall deeper than its posterior. Again advance the pivot to a" and let the end of the arm c cut a groove at the intersection of the arc b1 and the ring b, when it will be found that the anterior wall of this groove will not only be deeper than its posterior wall, but the difference in the depth of the two walls will be greater than at the intersection of b' with b. Suppose this ring extended into a tube, and it

B

B

FIG. IV.

с

will necessarily result that as the pivotal rod is advanced the arm e will rotate in the direction of the point b.

If for this ring we substitute the female pelvis for the fetal vertex, and for the arm c,