It has been stated,[61] that the first violent impression upon the brain, whether occasioned by an external force, or a “_coup de sang_,” from hemorrhage within the skull, will be very liable to produce syncope. This effect, when it occurs, ought of course to be distinguished from the more ordinary symptoms of concussion and compression, and which may be said to approach the nature of suffocation, rather than that of syncope, as they depend upon impeded respiration, from a failure in the action of the muscles which are essential to it. In the former case it would be highly injudicious to resort to the lancet, until the action of the heart shall have been restored by cordials; whereas in the latter, prompt and copious blood-letting must be considered as the most effectual of all the resources of art. For much of the novelty contained in this part of our work, the reader will find that we are greatly indebted to the liberality and friendship of _Mr. Brodie_, who afforded us the assistance of his _Manuscript Notes_, from which he delivered his lectures from the anatomical chair of the College of Surgeons. With regard to the manner in which the subjects have been individually elucidated, we may venture to hope that, in a work of such extensive range, the reader will scarcely expect to find every department equally elaborate in execution; our discretion on this point has been, in great measure, directed by the degree of importance attached to each subject, and the extent and nature of the popular fallacies with which it is surrounded. In dealing with subjects thus embarrassed we have ever deemed it a great point to clear away every adventitious incumbrance, so as to make a naked circle around the object in dispute, and to afford an uninterrupted view of it on every side. We have, therefore, in pursuance of such a principle, endeavoured to bring the leading points of controversy within the scope of a few prominent questions, that we might discuss the merits of each with a share of attention commensurate with our idea of its importance. The advantages of such a plan will receive, we trust, a favourable exemplification in our history of poisons. For our numerous quotations, if any apology be necessary, we may offer that of the learned _Tortosa_, deeming it more expedient to incur the charge of scholastic affectation, than to leave our readers in the dark, as to the sources from which we have derived our information, and particularly as we are thus enabled to furnish the student with various references to which he may advantageously apply for more extended information.