There is not much which is absolutely new in it. It is chiefly remarkable for the clear manner in which it places before us what is required, as distinguished from what is officious and unnecessary, and, in fact, reduces the treatment to that of ordinary cases, with one clearly defined modification. He shows his familiarity with Pneumatics, so far as they are touched by the case, just as he does his knowledge of Chemistry elsewhere. The exceptional cases, in which the air is confined in the chest, the mode of procuring it an exit by operation, and the condition regulating this proceeding, are very simply and clearly laid down. The paper also contains remarks on the collapse of the lungs when the chest is opened, and on certain exceptions which have been observed, which, from their general interest and suggestive character, will well repay an attentive perusal. He next offers a few remarks on those mothers' marks, as they are popularly called, and which are technically styled nævi. They are generally little more than clusters of enlarged blood-vessels, and are usually removed by excision or other operative proceedings. As the essential character of these marks is increased action and size of vessels, Mr. Abernethy thought that, if well-regulated pressure were made on them so as to impede the flow of blood into them, and this were conjoined with Cold (which represses vascular action), many of them might be got rid of in this manner. He found his idea realized, and published three cases of its success. The value of these suggestions consists, first, in the opposition they offer, _pro tanto_, to that absurd tendency there is to remove everything like a tumour; and the impediment thence arising to any searching inquiry into the causes on which they depend. But there is another inconvenience which occasionally renders the excision of these nævi very inadvisable. It sometimes happens that they are so situated that they cannot be removed, without making the disfigurement greater, or from some other still more serious objection; as, for example, when small ones occur in the face, or when they are placed near the eye. Under such circumstances, the contraction consequent on a wound of any extent is a serious inconvenience; in some of these cases, the adoption of Mr. Abernethy's plan allows us to dispense with the operation by excision, as I have myself experienced. As it illustrates the advantage of the plan in a case where it was particularly applicable, I will briefly refer to one example. A young lady had one of these marks at the root of the nose, where, from the position, as well as from the contiguity of the eyes, any dragging from the contraction of a scar, would have been particularly undesirable. She was brought from the country to have it removed; but, on representing the objections to that course, it was agreed to try Mr. Abernethy's plan, which was completely successful.