VOL. I. No. 3.

Health at School.

BY ALFRED CARPENTER, M.D. (LOND.), C.S.S. (CAMB.), President of the Council of the British Medical Association.

THE

No. II. SITE (continued).

I

HE floor of a schoolroom should always be raised above the level of the ground, and a free ventilation provided beneath it, so that no manufactory of morbid products should be possible. There should be no openings in the floor, through which unsuspected depots of sweepings may collect, so as to form a considerable heap of disease-producing touchwood, only requiring in the course of time a germ of morbid matter to fall upon it to enable it quickly to grow a quantity of infective material. The chinks in school floors are possible sources of danger which must be prohibited. A dry area should be constructed around the outside walls with which the sewers should by no chance be able to communicate. This area should extend below the level of the basement, and be carefully ventilated. have seen sewage conveyed through these areas; in earthenware pipes, a settlement has taken place on one side of the area; the change in level has broken the pipes and allowed the discharge of sewage into the area. This discharge went on for some time, and was not discovered until all the people of the house were laid up with typhoid fever. In another case in which an iron pipe was used for the purpose, the iron had oxidised at the point of junction with the outer wall, and sewage was discharged into the area. It went on for years quite unsuspected. There was a disagreeable smell in a library fifty yards away from the place of exit, which no efforts of the architect could remove until the hole in the pipe was discovered by accident. Much illness had been produced in that house for many years in consequence of this apparently unimportant defect.

It is right to remove from within the foundations all the subsoil which contains organic matter, excavating it until the virgin earth is reached.

If the latter is itself impure, as is the case in some deltas and other more recent formations, it should

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be removed for a certain depth; then, when convenient, covered over with chalk, and above the chalk several inches of concrete should be placed. If it be in a district in which the ground-water must sometimes rise and fall, it should be roughly asphalted, so as to reduce the evil to a minimum. The lime in the composition of concrete is of some service, for so long as it remains as an oxide it absorbs a certain quantity of the carbon anhydride (CO2) which may happen to penetrate it. Of course the greatest care must be taken to prevent the possibility of sewage pollution. This is one of the greatest dangers to which the fabrics of school buildings are exposed. It is not at all uncommon to find the subsoil polluted by these occasional discharges. Sites upon clay formations should be avoided where possible. If the geological formation is one of clay only, of course it cannot be helped; but if there is a choice, it will be found that the bed of clay is some degrees colder than a more porous subsoil. There is one advantage in clay-viz., it is not so liable to soakage from sewage; but this is fully counterbalanced by its disadvantages.

If it is proposed to place a school upon the side of a hill, the site must be carefully examined: bogs are found there as well as lower down, and any position which may cover an underground stream is bad. The foot of a slope or the bottom of a narrow valley is not good. If the side of a hill is chosen, care must be taken to provide that the buildings are kept perfectly clear of ground at a higher level. They should be raised so that the surface slopes downwards from the school-house towards the rising ground. The soil should never rise immediately upwards from the building so as to allow superficial drainage or soakage to take place towards the foundations. There should be room for the free play of air on all sides. The slope of a hill which rises abruptly, and which affects more than one side of the house, or a cliff coming close to the buildings, should be avoided, even if the site can be had for nothing. The top of a hill may be a disadvantage if it be so placed as to be exposed to the influence of malaria from distant marshes, or to the smoke and used-up air of some great town immediately below.

H

But high and bleak sites are better than low ones, when as regards the latter there are other things which are to their disadvantage. The neighbourhood of ground which is covered with rank vegetation is to be avoided; it indicates an impure subsoil. Sites which are sometimes obtained by filling up some old swamp or venerable pond are not satisfactory places for school-houses. It is probable that the conformation of the neighbouring strata tends to bring water in those directions, and to keep it there.

It is not good to have school-houses immediately and closely surrounded by trees, although a few trees in exposed situations, when kept away from the buildings, are highly advantageous. Everything which tends to allow of stagnation of air in and around the school is to be avoided; for this reason, high walls and other, lofty buildings are to be kept as far from the grounds as possible. It is seen sometimes that at a given spot on cold evenings a fog first appears in a given neighbourhood: that spot is one to be avoided. The bottom of a narrow valley is quite sure now and then to be invaded by an underground stream of water, and is not therefore a satisfactory site.

If there are trees, they should be to the north or east, and sufficiently removed to prevent them from acting as impediments to ventilation. Air and light are most important factors in the case, and nothing should be allowed to interfere with a due proportion of both being attainable on all sides of the buildings. In great cities it is not always possible to have trees in the playground; they are advantages when kept immediately away from the school-house. Light and shade are necessary parts of school life, and there are times even in this country when it is beneficial to have the direct rays of the sun tempered by the pleasant green of healthy foliage-they diminish evaporation from the soil beneath. The summer temperature is lower, and the cold of winter less in districts in which trees abound, than in those places where there are none; decaying vegetation is not, however, to be encouraged near to a school-house.

The building should be placed so as to obtain all the light possible. The prevailing winds should be considered, and the point made out from whence the largest amount of rain comes. The roof should be planned so that it shall carry off the water as quickly as possible, and as not allow it to be blown upon the side walls, thus rendering them perpetually damp. It may be necessary in rainy districts to have those parts of the school which are not continually occupied on that side of the building from whence the most rain comes. This, however, only applies to the rainy districts of the country. Every precaution should be taken to get rid of the rainfall, so that it shall not saturate the subsoil. To build a school-house without spouting sufficient for the purpose is bad. Every precaution should be taken to keep the buildings dry; the architect, as regards these arrangements, should be called upon to provide for the maximum rainfall on any day in the year, and not for an average only. It is the wettest seasons which test the work both of spouting and drainage, and in both cases it is the maximum fall or flow which is to be met, and not the average. It is the maximum which brings disaster when it is not provided for. The ill-health of a whole district may be an established fact, because a given school has been inundated by an unusually heavy

thunderstorm, in consequence of defective spouting and drainage. The position, as to the points of the compass, which the schools should occupy has also to be considered. The buildings ought so to be placed that every room should receive the direct rays of the sun during some part of the day. Verandahs are better avoided, and no architectural ideas of beauty should be allowed to introduce them if they impede direct sunlight. Exclusively northern windows are only to be admitted when required for ventilating purposes. To effect these objects, it is better for the school to be so erected that its corners are towards the points of the compass, rather than as churches are usually built, on its direct lines. It may be that the ground beneath the school floor has to be utilized as a playground; it is a bad arrangement, and should only be allowed when it is quite impossible to obtain further room for the purpose in proximity to the school. This point will be considered in detail when the subject of Bodily Exercise is considered.

No. III.-DRAINAGE.

A site without means for drainage must be declined at any price. There should always be a fall from the school-house capable of being utilized for drainage, and this fall should be adequate for the purpose of conveying it away. It should be more considerable for a small school than is absolutely required in the case of a larger one, and the smaller the rainfall of a given district the larger the fall should be; and it should never be less than 1 in 50. If there is a system of sewers into which the drains from the school are to discharge, there should be a man-hole at the junction with the main sewer, and the junction so arranged as to be capable of inspection without having to disturb the drain pipe. The junction with the sewer should never be at a right angle, but slanting in the direction of the stream of sewage. Stoneware or earthenware syphons are now manufactured to cut off all direct communication between the public sewer and the private house drain, which are good, provided they are examined occasionally; but if such a one is used, it ought to be provided with a ventilator between the syphon and the school-house, and be placed close to the trap of the syphon. The London Sanitary Company provide these. Stiff's interceptor is something of the same kind, and so is Pott's Edinburgh chambered sewer trap, and several other makers have traps which are equally efficacious, but all require occasional inspection. Impervious pipes are better than bricks for sewer purposes.

It should be an established rule that no sewer pipe should be allowed to penetrate within the main walls of any school building on any pretence whatever. There should be a most perfect interception; the sewer should carry off the sewage by means of communications which should be indirect only. Sewers are necessary evils in large towns and among great congregations of people. They have their dangers. It is not necessary to admit them within the precincts of the building, and if kept outside it is certain that they cannot act as channels for the conveyance of mischief when unsuspected. All premises, therefore, which have direct communication with the sewer should be in annexes, and kept outside the main walls. It may be convenient for the school staff to have W.C.'s close at hand, but the convenience is

small compared with the danger. The danger is small when they are properly constructed outside the building; it is enormous if they are brought within the fabric itself.

It should be an established rule, that all sewers should be laid on concrete in those parts of the curtilage of the school-house which are school property. This bed of concrete should be constructed before the sewer is laid down. It should be made according to the provided fall, and when once fairly laid, will for ever prevent that particular sewer getting displaced, except by extraordinary circumstances. Welllaid sewers may be the means of saving a great annual expense, as well as preventing evils which will sooner or later follow when they are badly laid.

The custom of the district will determine whether the rain-water from the roof goes into the sewer or not. It is a bad custom to thus send away a valuable commodity, but rain-water butts, as too often placed, produce mischief, from the dampness which surround them. The rain-water should be conducted into the nearest water-course, unless it be stored in properlyconstructed receptacles. It is a bad custom to allow the rain-water gutters to communicate with the sewer; and when the stack pipes discharge themselves into the ordinary house drain, the pipe should be trapped at its junction with the sewer, so that no foul air shall find its way beneath the eaves of the school, and then be conveyed into the nearest open window.

Anecdotal Natural History.

No. III.-BATS.

BY REV. J. G. WOOD, M.A., F. L.S., Author of Homes without Hands,' 'Nature's Teachings,' etc., AND THEODORE WOOD, M. E.S., Joint-Author of 'The Field Naturalist's Handbook.'

IN

N almost every temperate part of the world, but more especially abounding in tropical climates, are found the curious creatures which are popularly known as bats, and scientifically as cheiroptera, an appropriate word signifying 'hand-winged" animals. Australia, however, must be excepted, as the whole of the Australian mammalia belong to the Marsupials.

It is only of late years that their proper position in the scale of creation has been discovered. Before that time, some of the wildest conjectures were made on the subject. As the creatures possessed the power of flight, some authors placed them among the birds, entirely overlooking the differences in structure, which should at once have pointed out their place among the mammals. Some, considering them to be quadrupeds, because they were able to walk upon the ground, though after a rather clumsy fashion, imagined that they must form a connecting link between the mammals and the birds; and it was not until later discoverers carefully investigated their anatomy that the real place of the bats was arrived at, namely, just after the monkey tribe, and before

the cats.

The appearance of the bat is familiar to almost all, the strange membranous wings, enabling their owner to pursue their aerial evolutions with an ease and rapidity not exceeded by any bird, being the first points which arrest the attention.

Though possessing an almost equal power of flight

with the birds, the wings of the bat are by no means constructed upon the same principle. Instead of feathers, the wing is composed merely of a membrane tightly stretched between the bones of the fingers, and extending along the sides as far as the tail. In order to fully understand this structure, we must examine the modifications of the skeleton which render it possible.

In the first place, the framework of the wing of the bat is formed merely by the bones of the arm and hand, which, more especially those farthest from the body, are elongated to a wonderful extent, the middle finger being actually of greater length than the whole head and body of the animal. The only exception is the thumb, which is very short, and armed with a strong curved claw.

Not only are the bones of the fingers elongated, but those of the palm of the hand, or metacarpals,' are drawn out to an astonishing length, that of the thumb being excepted, as above mentioned.

If we spread our own fingers widely, we shall see that their bases are connected by a fold of skin which is hardly perceptible when the hand is closed. Now and then, it is extended as far as the first joint, and there are many of the mammalia in which it is still further developed. The seals which fly through the water have the hand membrane greatly extended, and other water-living mammalia have it developed in a lesser degree.

Then, the flattened skin-fold of the flanks is not peculiar to the bat tribe. It can be traced in the common squirrel, and in the flying lemus, flying squirrels, and flying opossums a similar structure is

seen.

In the lower part of the arm, that from the elbow to the wrist, there is practically one bone only, instead of two, as is usually the case, the reason of which is very apparent. It is owing to the two bones of the arm that we are enabled to turn the limb inwards and outwards at the elbow. If the bat were possessed of the same power, it would be impossible for the wing to strike the air with the steady beat necessary to flight, for the resistance of the air, turning the arm sideways, would allow the wing to cleave through it sideways, and the power of the stroke would thus be of no avail. As it is, however, there is one bone only, the bat is unable to turn the limb, which therefore always presents its full surface to the air.

The bones of the hand, too, cannot be clenched as in a fist, but possess a side motion only, enabling the wing, when not in use, to be folded closely against the body.

The membrane which forms the wing is merely a prolongation of the skin of the flanks and other parts of the body, stretched tightly between the finger-bones, and extending as far as or farther than the tail, which, in the insect-eating species, is included in it, serving, like the tails of birds, as a natural rudder by which the animal can direct its course. In the fruit-eating bats, however, where so great agility in the air is not necessary, the tail is left partly or entirely free, and is much used in climbing and walking.

The membrane is a double one, very thick in those parts contiguous to the body, but so delicate near the edges, that by the aid of a microscope the blood corpuscles can be seen passing along the vessels that supply the wing.

Though the powers of flight of the British bat are fully equal to those of many birds, they have never been known to migrate from one country to another, and it is very doubtful whether they possess the ability. For bats have none of the large auxiliary air-cells found in birds, acting as a sort of reservoir, and their bones are not permeated with air-cells as are those of the feathered migrant.

There are, however, several bats belonging to the

genus Mycteris,

would think, extremely uncomfortable attitude the bat always rests, and passes the winter in a torpid condition.

It was remarked many years ago, that the bat possessed a most wonderful power of avoiding any obstacles that presented themselves in its path, and that it could pass among the branches of trees, even where the twigs were thickest, without coming in contact with them. In order to ascertain whether this was always the case, a number of strings were stretched in a darkened place, and several bats let loose among them; yet it was found that the animals avoided them with the greatest ease. Thinking that this power might be the result of an unusually keen eyesight, one investigator, named Spallanzani, in a very cruel experiment, put out the eyes of a bat, and again let it fly, but was surprised to see that the creature avoided the objects exactly as before. It was then thought for many years that the bat possessed a sixth sense unknown to man, and it was not until comparatively lately that the true secret was discovered.

found in Africa, which possess a somewhat similar apparatus, though not constructed upon quite the same principles.

The skin is very loosely fastened to the body, a few membranous threads being the only bonds. The space between this loose skin and the body is utilized as an air reservoir, and is filled as follows. At the bottom of the cheek-pouches on either side is found a small opening, which can be closed at the will of the animal, and the air prevented from escaping. When the bat wishes to inflate its body, it closes the mouth, and forces the air from the lungs through the cheek-passages into the vacant space. To such an extent does it inflate itself, that it loses all resemblance to a bat, and looks merely like a round ball of fur provided with head and limbs.

The objects of this curious structure are not known, besides the evident one of increasing the buoyancy of the animal.

The shoulder-blades of the bat are enormously large, almost covering the whole of the ribs. These also are large and strong, and the breast-bone, besides being of unusual length, is furnished with a central ridge, or keel, like that of birds, for the better attachment of the powerful muscles which work the wings. The rest of the skeleton is of the very slightest description, in order that no unnecessary weight shall hamper the movements.

The feet are very small in proportion to the rest of the body, and are furnished with long curved claws, which are of assistance in walking, but are chiefly used in assuming the extraordinary posi

tion of rest, when the bat hangs Keeled Breast-bone of head downwards, from some con

Bat.

venient ledge or beam, merely hooking itself on by means of the claws. In this strange and, one

A careful examination of the membranes of the wings and ears showed that they were intersected by exceedingly delicate nerves, and it was found that the bat was thus made aware of the neighbourhood of an obstacle, and enabled to avoid it accordingly.

The fur of the bat is of a very soft and silky nature, and the hair is a most beautiful object under the microscope. It is densely clothed with scales somewhat resembling those of a butterfly's wing, which are arranged in circles round the hair, a short distance from each other. The whole object bears a wonderfully strong resemblance to the well-known mare's-tail plant.

Easy and graceful as are the movements of the bat whilst disporting itself in the air, it is a very different creature when attempting to walk upon a level surface. Its mode of progression can at best only be described as an awkward waddle, the creature hitching itself along by means of the claw at the extremity of one of the wings, giving a kind of tumble forwards, at the same time advancing the corresponding foot; the same process is then repeated with the other wing.

The

In the illustration representing the bats in a cave, the extraordinary attitude assumed in walking is well shown. The long finger-joints are pressed together, their tips projecting on either side of the back. weight of the body rests on the wrist, and the creature pulls itself forwards by hitching the claw of the thumb. upon any roughness of the surface on which it walks.

Bats are remarkably averse to taking to the wing from a level surface, and always prefer to climb to some little height from which they can throw themselves into the air. This is evidently the reason for the strange and apparently uncomfortable attitude adopted when at rest, the animal being then in the most convenient position for launching itself into the air should there be any signs of danger.

It has been sometimes said that the bat is unable to rise from the ground, but such is not the case; and should the creature be hard pressed, it does not hesitate to do so.

It is able to climb with tolerable facility, and always does so with the tail uppermost, making its way up by the aid of the hind feet, the long claws of which are inserted into any convenient crevice in order to gain a foothold.

The food of all the British bats consists of the various small insects which fly about dusk, and at that time people the air in myriads. The appetite of the ani

mals is almost insatiable, as may be gathered from the fact that a specimen of the short

eared bat, lately kept in captivity by ourselves, consumed daily from forty to fifty bluebottle flies of the very largest dimensions, rejecting only the wings, and in a few

an inch or so of it, with a sudden spring, clutched the insect between the wings, and holding them tightly together, bent down its head, and swallowed its captive. If a fly happened to take flight before the bat was near enough to make its spring, it merely remained motionless until another presented itself.

It was fiercely voracious when it once began to feed, and scarcely had one fly been swallowed than the bat was eagerly looking out for another. Its attitude when thus engaged strongly reminded us of that of the toad or the green crab when hunting after prey.

Though as a rule a nocturnal creature, owing to the habits of its prey, the bat may occasionally be seen flying in broad daylight, and sometimes, in the early spring, even hawking for the insects which are enjoying the warmth of the sun. In these cases, it is probable that the bat, having for the first time left. the retreat where it had passed the winter in a torpid.

cases the legs. Even upon this allowance, which seldom occupied it for more than twenty minutes, it did not thrive, but gradually wasted away, and finally died.

The bat was one which had been found in a hollow tree, and suffering from an injury to one of the wings, which entirely prevented it from flying. It was kept under a glass shade, into which the blue-bottles were introduced. It never took the slightest notice of the insects until nearly dusk, allowing them to crawl over all parts of its body without manifesting the least signs of activity. As soon, however, as the day began to close in, it was on the alert, and immediately set to work devouring the flies which had been procured for it.

This it did in the following manner :

Resting upon the floor of its cage, it remained motionless until a fly settled within a few inches. It then began, by an almost imperceptible movement, to approach the insect, and when within

condition, has felt the want of food, and knowing instinctively that no insects would be on the wing at sunset so

early in

the year, has so far altered its usual habits as to prosecute its search by day instead of by night.

Most

bats, however, re

sort to

dark and

retired hiding-places during the day, and in some parts of the world there are large caves which are celebrated as haunts of the bats. When travellers visit these caves, the guide will fire a gun into the cave for the purpose of startling the bats, which come rushing out in such numbers that unwary visitors have been fairly knocked down by them.

In Great Britain alone, there are nineteen catalogued species of bats, many of which, however, are rare, and very seldom seen. One of the commonest is the Long-eared Bat (Plecotus communis), which abounds throughout the British Islands. It derives its popular title from the great length of its ears, which stand out for some distance from the head, and which are thrown at every moment into a variety of graceful folds. In consequence of its gentle temper, this bat is easily tamed, and is often kept as a pet, coming when called by those with whom it is familiar.

Another of the British bats is the Noctule, or