becomes rigid and preternaturally concave, whence this action is prevented by the shoe and nails. In this hard and fixed state, it offers a solid resistance to the pressure of the coffin-joint from above, instead of yielding to it as it ought to do; this is enough to occasion inflammation of that joint, and its train of bad effects.

I have only one question more to ask the gentlemen who consider navicular disease as the prevailing evil. How are they aware of its existence ? What are the diagnostic symptoms (for hitherto no one has described them) by which they know that it is present in a living horse's foot? As dissection alone can furnish proof of the truth or error of their verdict, such evidence is seldom appealed to; but, at the London slaughter-houses, there are too many miserable and hobbling cripples, and I challenge those who maintain this complaint to be more general than contraction, to a trial of their foreknowledge respecting it.

And now, Mr Editor, I must request you to excuse the length and warmth of this communication. I have stated my reasons for believing that this affection is comparatively very rare, that it cannot be predicated with certainty, and that, when it does exist, it is only one of the ruinous effects which result from the unnatural practice of fettering a living elastic organ with an unyielding ring of iron-a proceeding which, familiar as it has become, is still at variance with every principle of anatomy and physiology, and which every day's experience proves to be erroneous. I am, &c.

[We have pleasure in giving insertion to Mr Clark's interesting communication, and are desirous that the question to which it relates, and which has already excited considerable discussion, should be fairly argued. On this account we shall give an opportunity to our friend Mr Dick to make his remarks in our following Number; and we feel assured that both gentlemen will terminate the discussion with the good temper and good feeling with which such questions should be argued. We regretted that Mr Clark's paper was too late in reaching us for insertion in our last number.-EDIT.]

ON THE STOMACH PUMP, AS APPLICABLE TO THE DISEASES OF DOMESTIC ANIMALS.

Ar this season of the year, when cattle feed on green and

succulent food, there are perhaps few diseases so common amongst them as that of hoven or inflation in the ruminant. The complicated structure of the stomachs of ruminating animals, renders them peculiarly liable to this disorder, the paunch being a kind of reservoir into which the food is received. In it the food is mixed with the animal fluids; the minute particles are passed onwards through the second into the third stomach, while the coarser parts are again sent up to the mouth to be further comminuted, by undergoing a second process of mastication.

As the paunch is of an immense size in these animals, and as the green food which is taken into it is frequently much overcharged with moisture, and otherwise in a state which renders it liable to fermentation, it often happens, that when the stomach becomes overloaded with this kind of food, the fermentative process goes on with a great degree of rapidity, in consequence of the stomach being, as it were, overpowered and unable to carry on the operation of digestion. This the more readily takes place, because there is a sweetness in the grasses at this season of the year, more especially in the after-math or second crop of clover, which induces the animals feeding on such food, frequently to take an undue quantity. In this fermentation a large quantity of air is generated, by which the stomach becomes so over-distended, that either a rupture of it takes place, or the respiration being interrupted, impedes the action of the diaphragm, and the animal becoming unable to breathe, dies of suffocation in a short time, perhaps in a few minutes.

When such is the often fatal nature of this disease, it be comes a matter of vast importance to know what is to be adopted as a remedy. The means that have hitherto been employed for this purpose are various. The first thing which it is desirable to accomplish, is to restore the tone of the stomach, so that its vital energy may, if possible, overcome the disease.

If this cannot be accomplished, a method is adopted of allowing the air to escape, or of removing the accumulated matter from the stomach. To assist the weakened state of the stomach, it is found that any stimulant may be given with benefit;—any spiritous liquors, as rum, gin, whisky &c. in large doses; any oily fluid, as olive, linseed, castor, or even train oil, and melted lard or butter, but more especially the essential oils, and of these in particular turpentine; various stimulants, as the carbonate or water of ammonia, spirits of wine, and nitrous or sulphurous ether; aromatic seeds, as pepper, mustard, &c.; resins and gums, as tar and rosin; various tinctures, as opium; several acids, as the acetic and muriatic acids; and alkalies and alkaline earths, in particular lime-water.

But although each of these has occasionally been found to give relief, there are cases which do not yield to such treatment; and recourse is then had to the introducing a hollow tube through the mouth and oesophagus, and allowing the air to escape through it from the stomach. If this does not succeed, or should the proper instrument not be at hand, an opening is made through the side into the paunch by a pen-knife, or with a trocar and canula, and the air allowed to escape as it is formed. But there are cases in which, from the enormous quantity and solidity of the matter taken into the stomach, even these means all fail, and an incision is then made through the side into the paunch, large enough to allow a person to introduce his hand and extract the contents; by this means animals are often saved. Such a formidable operation, however, from the manner in which it is performed, and the effects which frequently follow, ought, if possible, to be avoided. As there is a degree of play between the peritoneal surface of the stomach and the peritoneal lining of the parietes or sides of the belly, there is of course, considerable danger of a portion of the matter in the progress of extraction getting into the cavity of the abdomen; and this, by producing irritation between the two surfaces, causes an inflammation to take place, which frequently destroys the life of the animal. And although these animals are less susceptible of inflammation in this membrane than what might be expected from its sensibility in other animals, still the danger

consequent on such an operation must be considered of sufficient importance to induce us, if possible, to avoid it.

The success which attended the operation of the stomach pump upon the human subject, and the high and deserved esteem in which it was held, called the attention of scientific men to the invention of a similar instrument for the uses of domes tic animals; and the very ingenious one invented by Mr Read of London, for which he obtained a patent, has attained this object in a most satisfactory manner. This This pump is calculated in an eminent degree to supersede the necessity of adopting the dangerous and frequently inefficient modes which we have enumerated, and to afford immediate relief to the animal. The pump is chiefly required for withdrawing fluids from the stomach. When the consistency of the mass, however, is such as cannot be operated upon by the pump, liquids can be injected by means of it so as to dilute the mass, and the whole can then be withdrawn.

Mr Robert Rettie, brassfounder in Aberdeen, has transmitted to us an instrument of this kind made by himself, a figure of which is given below. The workmanship is executed in a very superior manner, and the instrument seems perfectly calculated to effect the purposes intended. The chief difference between it and that of Mr Read, consists in the construction of the valves. In Mr Read's, the valves are balls resting in sockets, with space to move when the air is exhausted by the piston. In Mr Rettie's instrument, the valves are half balls, with a space also allowed to play, but retained in their places by gratings.

A is a cylinder of brass in which the piston works.
B is the piston, which is shown drawn partly out.
C is an elastic tube, composed of leather, covered with plaited
tharm, and varnished over with a coating of elastic gum.

It is about five feet in length, and seven-tenths of an inch in
diameter.

D is the end of this elastic tube, a little enlarged, and in the

shape of an egg, which is perforated with four small holes, to allow the fluid to be drawn up through the tube. The other end of the elastic tube is attached to a short tube of brass

E, which is fixed by a screw to the cylinder at G. At the point
of junction here, is one of the sockets with its semi-globular
valve.

F is a bent brass tube, through which the fluid which has been
drawn up is ejected by the action of the piston. On the
extremity of the tube F, is a male screw of the same size as
that on the end of the cylinder. At G, as has been stated,
is a socket and half ball; and near the end of the tube at
F is a similar socket and half ball. These balls are pro-
tected above by a grating, as already mentioned, which
allows fluids to pass, but does not allow the half ball to turn
over. By drawing the piston out, the valve at F shuts, and
the one at G opens, and allows the fluid to pass up through
the elastic tube; and by pressing down the piston, the valve
at G shuts, and the fluid is ejected through the tube F.
If the action is to be changed and fluid injected into the stomach,
the tubes are reversed; the elastic tube is screwed on to the
curved pipe F, so that water or other fluid may be drawn
into the cylinder at G, and forced by the action of the pis-
ton through the bent tube, and along the elastic tube, into
the stomach.

The elastic tube may also be used as a rammer for cattle or sheep, in those cases where obstruction arises from a piece of turnip or other substance being lodged in the throat. In this case, the brass end of the tube is put down the throat, and the piece is thus dislodged. In the figure and description which we have given, the instrument is on the large scale, as adapted for cattle and other large animals; but, with smaller tubes, the