toneal cavity through the circulation into the bladder in seven minutes.

With the recognized rapidity of peritoneal absorption in extensive and dangerous hemorrhage, peritoneal injection of normal salt solution might save life.

The rapid fluid absorption by the peritoneum teaches against irrigation in laparotomy, from the fact that the germs would become widely and rapidly distributed, especially through the diaphragm.

one may note the leucocytes distinctly beneath the cover-plate in various positions in the interendothelial space.

A.

Occasion

B.

Fig. 95 (Author). Two endothelial groups drawn from two places in a horse's mesentery. 1, 1, in A and B, point to stomata vera; 2, 2, in A and B, point to the nuclei of the granular cells which surround the stomata; 4, 4, in A and B, are endothelia; 5, 5, stomata vera; 6, black point on endothelial cell. In B, it appears that the stomata vera are peeking up through the endothelia, or they are shimmering through it.

ally we may note either end of the middle portions of the leucocytes clamped between the adjacent borders of the cover-plates, or finally the leucocyte may be seen on the peritoneal surface.

The function of the leucocytes seems to be (a) to surround the foreign body and transport it into subserous lymphatics; (b) to bury the foreign body; (c) to digest it, or (d) to sterilize it by imprisoning and isolating it by exudates. If one leucocyte be unable to bury a foreign body, many will come to the aid.

Whatever tends to induce migration of one leucocyte seems to call out swarms of leucocytes.

Fig. 94 (H. for Phys. Lab., 1873). Mesentery of dog, prepared with gold chloride, showing the distribution of sympathetic nerves to a blood vessel, a, b, forming a nerve plexus around it.

White blood corpuscles appear to be continually passing into and out of the peritoneal cavity.

The function of the leucocyte may be tested by the injection of fluid containing solid particles in suspension into the peritoneal cavity. A few minutes after such fluid is injected into the peritoneum, the leucocytes begin to swarm on the surface of the peritoneal endothelia. By observation in different stages of the experiments,

emerge to protect invasions against the peritoneum, viz., by digestion, imprisonment, transportation or sterilization of the foreign, by its vegetable germ or inorganic particle.

0

Fig. 97 (Author). Drawn from rabbit's omentum. The rabbit was killed by ether, the abdomen was carefully opened, and in situ the omentum was brushed with cotton on a tooth pick, after which distilled water was poured on. It was then stained with one-half per cent of Ag. NO, for four minutes and mounted in glycerine. cs, stomata spuria; sv, stomata vera open.

The membrana limitans is a thin, ground-glass-like membrane, resembling the wall of a soap bubble, on which the peritoneal endothelia rest. Brushing the endothelia off, leaves a pit-like depression in it.

The membrana limitans, or basement membrane, is found to be perforated by numerous apertures on the diaphragm (centrum tendineum) only, and this anatomical fact serves as physical or mechanical explanation why the chief, and perhaps only, locality of the peritoneum which absorbs solid particles held in liquid suspension is the diaphragm.

The enormous activity of the diaphragm in absorption makes it an intensely dangerous locality for infectious invasions.

The dangerous areas in peritonitis are these places of active absorption, and the diaphragm and small intestines-for absorption and infection kills, while peritonitis (exudates) saves life. The benign areas, the safe areas of peritonitis, are those areas of slow absorption where exudates form. The benign areas of the peritoneum are those of the large intestines, i. e., the pelvic splenic, the appendicular and gall-bladder region. The dangerous area is that of the small intestine.

The vast, loose and shifting and spongy bed of snow white connective tissue, on

which the peritoneum rests, especially in the dorsal region, endows the peritoneum with an elastic accommodation for the movement and shifting of organs. It serves as a sifter to lessen trauma. It is endowed with much capacity to circumscribe and tolerate local infectious material.

The capacity of the subperitoneal tissue to split and resplit into fine, smooth planes allows the infectious fluids to move in many directions for accommodations and escape. The fluids penetrate in the direction of least resistance, which is well recognized by clinicians as to the movement of pus in the pelvis and psoas muscle.

The histology of the subperitoneal tissue teaches why the viscera can shift as in visceral ptosis. The displacement of the viscera seems to be chiefly checked by the two factors (a) the blood vessels (arteries) and nerves and (b) the membrana mesenteric propria.

The automatic power of the peritoneum to secrete the proper amount of fluid to facilitate motion of viscera is a very delicate physiologic process.

A difference in function between an endothelial and an epithelial cell, is that an epithelial does not normally secrete albumen, while an endothelial cell does.

Fig. 98 (Author). A new born human omentum, showing stomata vera and spuria. 1, 2, 3, 4, stomata vera; 5, stoma spurium; 7, 8, surface endothelia; B, from foetal pig (two month's old), peritoneal surface of diaphragm; 1, stoma verum; 2 and 3, endothelia.

Epithelial and endothelial cells are both alike bound in colonies of protoplasmic processes.

If the peritoneum be siivered very lightly for a short time, say, one-fourth per cent, for a minute, it can be re-sil

vered, and also treated with other reagents, fixing or coloring it.

The peritoneum may be viewed as a joint of vast physiologic activity.

Endothelium varies in shape and kind, according to the organ on which it is lo

Fig. 99 (Author). Human omentum of woman 30 years old, dead thirty hours. 1, 1, common endothelia. The germinating and common surface endothelia require a different microscopical focus. The germinating is elevated above the surface. 4, show vaculolation which will result in a lymph sinuses. cated. In general it is more regular in outline if it be on an organ which is quiet, i. e., if it rests on an unmovable base it is quite regular in shape and outline. If the endothelia rest on a movable base, as many of the viscera, the endothelia take a shape which elongates in the direction of expansion and contraction. In the vessels,. however, the endothelia are elongated in the direction of the fluid stream. On the expanding and contracting bowel, the endothelia generally elongate in a direction transverse to the fecal current, i. e., transverse to the bowel. Thus very great irregularity of fluid expansion, and the indefinite direction of its current at various periods. The endothelia over the ovary assumes a germinal character. It assumes a columnar shape. Germinating endothelia in general are not so felt or squamous as the common peritoneal endothelia; are smaller and rounder in outline than the adjacent endothelia. The endothelia over the kidneys are comparatively uniform in size, and hexagonal in contour.

'The peritoneal is equal in area to that of the skin. Its absorptive power is far greater than the skin.

The peritoneum has a limited power to resist septic germs. At present we have no standard by which the power may be

measured. The power to resist septic germs is slightly different in different animals. The peritoneum of the pig, rabbit, and cow resist considerable quantities of septic organisms. The mare's peritoneum is so sensitive to septic germs, that laparotomy on her is almost always fatal. The dog and man are about equal in their power to resist peritoneal invasion of pathogenic germs. Some, however, claim that the peritoneum of the dog resists more than that of man.

The peritoneum presents the most favorable conditions for healing.

The different degrees of vulnerability in the peritoneum, in all probability, rest on its close relation to its lymphatic structure.

The peritoneum is peculiarly sensitive when inflamed. The nerves of the peritoneum are vast in extent and number. They are (a) medullated; (b) non-medul

Fig. 100 (Author). Dog's gastro-splenic omentum, 3 months old. The darkly shaded area is germinating endothelia. 1, 1, surface endothelia; 2, 2, germ. inating endothelia; 4, 4, stomata vera. The germinating endothelia project above the common endothelial surface. Great numbers of germinating patches lie adjacent to this.

lated and (c) various forms of terminations, as the Vater Pacinian corpuscle. The kitten is one of the best animals to demonstrate the peritoneal nerves. Acetic acid and gold chloride are the best reagents.

The numerous terminations and vast area of nerves in the peritoneum account for the profound shock which is intimately and closely associated with the caliber of vessels, controlled chiefly by the sympathetic nervous system. Reflexes from the peritoneum are most profound on distant viscera.

Peritoneal surface lessens with ascending scale of mammalian life. Man has, proportionately, the least amount of peritoneum of mammals. Man's omentum majus (mesogastrium) is much smaller than that of many mammals.

Through ages of evolutionary processes of infective invasion, the pelvic splenic, appendicular and gall-bladder region (the region of the large intestine), has acquired a physiologic immunity which resists the infectious germs, in the common regions of peritonitis. Repeated inflammation has obliterated the lymphatics. It appears that the lymphatics are less in the region of the colon, hence the benign region of peritonitis. The lymphatics are more numerous in the region of the enteron or small intestines, hence it is the region of absorption, the fatal peritonitis.

(Concluded.)

[Written for the MEDICAL BRIEF.] Decay of the Teeth and Disease of the Gums.

BY FRANK EATON BURNETT, D. D. S., Chicago, Ill.

(Continued from page 1021.)

From early youth we have to do with decay of the teeth and disease of the gums, both easily prevented, as we shall show, as they are but a condition of uncleanliness.

Nature forms the teeth with curves, planes and crests, and locates them in such position relative to each other, that the passage of food over the various surfaces, together with the movement of the tongue, lips, and cheeks, produces a natural condition of cleanliness. This condition is modified in proportion to abuses, habits, faults from youth, and the influence of modern diet.

It may not be generally known that decay is ever repeating itself in exact and

certain parts of each tooth; it does not happen miscellaneously over the tooth's surface. The enamel is so hard that decay can not penetrate it in a day or a week. With this knowledge of the places liable to decay, and the time necessary to penetrate the armor (enamel) of the tooth, the dentist of the future will have as his mission to prevent the dissolution of the tooth .substance by the decay germ. His object will be to check the colonization of the decay germs at the favorable places they seek to locate; these are the deep fissures or pits in the teeth and the spaces between the teeth and at the gum margin. Normally the space between the teeth is filled with gum tissue, supported by a little spine of bone arising from the jaw. From prodding with a toothpick or from the sting and poison of debris this little spine recedes, the gum follows, leaves the enamel, where thinnest, also the root, exposed, and the space between the teeth open for the lodgment of foreign matter. Of all decay, the most destructive is found at the gum margin, particularly because it is, as a rule, permitted to ravish unnoticed.

From the soil accumulating and fermenting between the teeth, a little pocket or depression in the gum is formed; this is increased by food stuff crowding in and bruising it, or through picking with a toothpick. It is a very, very painful and disastrous condition, and in the later stages does not invite correction.

If a tooth be extracted, the opposing one immediately begins to emerge from the socket because of the lack of antagonism, the membrane which maintained it in place becomes thickened, and true inflammation exists. This membrane between the root of the tooth and the bone of the jaw, conveys the sense of touch; its health is largely dependent upon the health of the gums, if the latter be inflamed, the condition is reflected to this membrane. If the irritant be great enough, this root covering membrane becomes swollen, the tooth necessarily is raised in its socket, and being bit upon, responds with pain equal to that of an exposed nerve. Thus, one will notice disease of the gum is as common and painful, and as much to be avoided as decay.

Almost the entire care of the mouth, if begun early enough, and carefully observed, will come under the head of cleaning.

Those who have had that terrible disease of the gums known as pyorrhea, would gladly have had this protection and prevention. Pyorrhea is a disease resulting from the deposits upon the teeth underneath the gums. The inflaming gums recede from the ever present poison, while the deposits become deeper and larger, until the tooth may be lifted from the socket. The early stages are characterized by bleeding gums and looseness of the teeth, which may become loose enough for the tooth to drop out unaided. Indeed, the most beautiful teeth you have ever admired may be so afflicted, and may come out, as the patient may describe, "without apparent cause."

Further reference to this disease is made later.

The section of a tooth many times magnified.

A. Colonies of germs imbedded in foreign matter-which have become loosened from the enamel B. B. to C. enamel-D. Dentine, or bone of the tooth. E. Junction of enamel with gum, the darkened area is decay.

With no disposition to challenge technical criticism, we venture the suggestion that the retrogressive condition of the mouth is associated with intellectual growth. In the higher education of the man of to-day, we see exemplified the growth of the mental man, whereas the life of our ancestors represents the physical growth. As the mental area is nourished, correspondingly is the physical neglected.

The jaw is but the connecting link between the mental and physical man, and in

the measure and nature of the demand made upon it, so will that jaw evolve. Compare the plain and coarse diet of the aborigines with the cakes, creams, puddings and prepared foods of to-day, requiring no mastication; need we ask if Nature will maintain in the jaw and teeth of the present age the powerful grinders they were formerly.

In order to secure the true form of the jaws, they must be given their proper use; the crushing of hard foods is the true exercise, and is also essential in maintaining the physiological condition of the gum tissue and muscles of mastication.

Indeed, we have to-day, in the mouth, the living proof of this evolution; in that the jaw is shortening, and the wisdom teeth are frequently missing, and when present, are of but very irregular type, and often crowded out of place. The excessive pain accompanying the eruption of the wisdom tooth is caused by the effort of this tooth to crowd itself into too small a space. The vestibule of the mouth (that portion between the teeth and the cheeks) is, frequently, so small, in the vicinity of these last teeth, that the removal of the wisdom tooth often serves to make the mouth more spacious and self-cleansing in these parts, and saves the next teeth from the contaminating influence of a decaying wisdom tooth.

But not alone does the anatomical form change. The flabby, loosened and bleeding condition of the gums is but evidence of the sting and inflammation resulting from the chemical action of acids and alkaloids, the deposits from savory dishes, palatable drinks, medicines and what not. These deposits on the teeth are as equally dangerous to the gums as are the decay germs to the teeth, and their removal insures the return of the plump, hardy condition of the former.

The first particle of foreign matter that seeks a place under the free margin of the gum and remains sufficiently long to destroy the natural contact of the gum with the teeth, is the forerunner of the disease of the gums to which reference has been made.

Cure when in its first stage is very possible, and is included in that same cleans