and of chemical tests, because the conversion of phrases into facts gives measure of their relative value, and is at the same time an exercise of patience and of judgment-in short, because it is a rational discipline, as well as a useful technique. Nor is this all. An acquaintance with at least the existence of frontier interests, and even a participation de tactu with science at its growing surface, cannot be excluded from the laboratories of a medical school without serious and immediate loss to the interests of medicine and of surgery. With regard to the plan of construction of this book. The chapter headings are intended to serve a double purpose: as a summary or syllabus-being, in fact, the condensed lecture-syllabus that I have used during the last nine years; and as a means of self-examination. A student having read certain paragraphs or chapters, should return to the chapter heading, and find by its recapitulation whether it contains expressions that are meaningless to him, or whether it recalls a series of ideas that he has understood and assimilated. If an unfamiliar technical word is met with, its meaning should be ascertained at some other part of the book, through the index. Certain subjects are more difficult than others; some are more suitably studied during the first year, others during the second year; others, again, are difficult and of practical importance, some are difficult and of scientific importance; one subject may deserve days or weeks of study and require thorough analytic treatment, or be adapted to experimental demonstration; others may be more lightly passed over. Detailed guidance in such matters will be supplied by the discretion of the teacher, and by the traditions current among examinees; but in order to give some general guidance to the private reader, occasional use has been made of an asterisk in the chapter headings. In Part I. the sign has been freely used to indicate portions upon which a first-year student should not spend time if he should find the subject difficult. In Part II. the sign has been sparingly used, to indicate portions of undoubted difficulty, which can be omitted by a second-year student who is not reading for the higher examinations. Subjects of unmistakable difficulty in Part II., such as the brain, vision, &c., have not been so marked, because their great practical importance demands early and patient study from every student of medicine. The descriptions of figures are to be regarded as forming part of the text, inasmuch as they frequently contain statements of fact that are not included in the text. The Appendix contains matter that was felt to interfere with continuity of description in the main account of physiological phenomena. I have given a Bibliography after some hesitation, feeling that references to original papers are of no use to junior students, and must be too imperfect to be satisfactory to more advanced students. But doing so has allowed the text to be lightened of names, while preserving for the student who may inquire further the authorities for the principal statements made. Moreover, the chief use of a bibliography in a general text-book is to afford a few main startingpoints and indications, to be followed up in the year-books and archives of a well-equipped library; and even for junior students, it ought to be of some assistance to know whether doctrines and statements date from last year or from last century. The year of publication has been given in each case, leaving the particular page of a particular paper to be looked up in the index of the journal to which reference has been made. The preparation of a new edition has given me the opportunity of making several corrections; I have also made some alterations and transpositions of text that seemed to me to be desirable. Attention has been paid to recent work, but I have felt that the gradually-formed deposit of accepted knowledge must be of greater intrinsic value than the latest 'discovery' or the newest theory. An early mental diet in which these items are predominant is an unwholesome diet; their function in elementary instruction is that of condiments, valuable only in conjunction with a foundation of solid food, serving above all to teach that the Institutes of Medicine' are not a museum of dead dicta, but a living knowledge, of which the verbal formulæ are unstable-least unstable in the older strata, most unstable at the growing surface. I have therefore deliberately abstained from mentioning many matters that I have heard of or read of, and such recent investigations as are mentioned I have, for the most part, either worked at myself or seen worked at by others. I am indebted to many friends and fellow-students for information and for criticism; to Dr. Mott and to Professor Sherrington re the spinal cord, to Professor Delépine re the liver, to Professors Halliburton and Wright re nucleo-albumins and coagulation. A. D. W. September, 1893. |