The construction of a cupping-glass which shall attract without the aid of fire. Let A B C (fig. 56), be a cupping-glass, such as is usually applied to the body, having a partition across it, D E: through the bottom of the cupping-glass let two sliding tubes be inserted, F G being the outer tube and H K the inner; and in these, but outside the cupping-glass, pierce corresponding holes, L and M. Let the inner extremities of both the tubes be open, but the outer extremity of H K be closed and provided with a handle. Under the partition D E place another pair of sliding tubes, N X, like those just described; but the corresponding holes must be within the cupping-glass, and be precisely adapted to a hole in the partition. When these perforations are complete, let the handles of the sliding tubes be turned round, so that the holes in the lower tubes may be in a line, while those under the partition, not being allowed to coincide, remain closed. Now, the chamber D C being full of air, by applying the orifice L M to the mouth we can suck out a portion of that air; and then, by turning the handle again and not removing the tubes from the mouth, we can keep the air in the vessel C D rarefied; and this must be repeated until we have drawn off a large quantity of air. Then, applying the glass to the flesh in the usual manner, we open the holes in the sliding tubes N X by means of the handle; and it must follow that some of the air in the vessel A D E will pass into the place of the air withdrawn from C D, while into the void thus created both the flesh and the matter about it will be drawn up through the interstices of the flesh which we call invisible spaces or pores. 57. _Description of a Syringe._ [Illustration: Diagram of apparatus as described in text] The instrument called a pyulcus acts on the same principle. A hollow tube, of some length, is made, A B (fig. 57); into this another tube, C D, is nicely fitted, to the extremity C of which is fastened a small plate or piston, and at D is a handle, E F. Cover the orifice A of the tube A B with a plate in which an extremely fine tube, G H, is fixed, its bore communicating with A B through the plate. When we desire to draw forth any pus we must apply the extreme orifice of the small tube, H, to the part in which the matter is, and draw the tube C D outwards by means of the handle. As a vacuum is thus produced in A B something else must enter to fill it, and as there is no other passage but through the mouth of the small tube, we shall of necessity draw up through this any fluid that may be near. Again, when we wish to inject any liquid, we place it in the tube A B, and, taking hold of E F, depress the tube C D, and force down the liquid until we think the injection is effected. 58. _A Vessel from which a Flow of Wine can be stopped, by pouring into it a small Measure of Water._ [Illustration: Diagram of apparatus as described in text]