In presenting to the public the present stereotype edition of this work, it is proper to state, that no labor or expense has been spared to render it still more worthy of the kind approbation with which it has been received. A large proportion of it has been entirely re written, many corrections have been made, and numerous and highly valuable illustrations introduced; these improvements, together with the questions at the end of each chapter, cannot but render the work better adapted to the objects for which it was written.

The author natters himself that this treatise will be found to contain the substance of what is yet known on the subject of Human Physiology, and most that is valuable, which is scattered through many learned and ponderous volumes. In preparing it, more than fifty different works have been consulted, from all of which the author has freely taken whatever he found adapted to his purpose. Originality has not been aimed at, as it was precluded by the very nature of the subject; indeed it would have been unsuited to the object in view.

From the rapid sale of the first edition, and the numerous orders for the work from all parts of the United States, it may safely be concluded, that Physiology is henceforth to be one of the common branches of knowledge taught in our schools, academies, and other seminaries of learning. Indeed it is remarkable, that sciences, so closely connected with the health and happiness of our race, as those which teach us the structure and functions of the human body, should so long have been confined to those who intend to pursue the practice of medicine and surgery as a profession, especially when the practical application of such knowledge is daily and hourly of the utmost importance to every individual, connected as it is, with the preservation of health and of life. That such studies are not above the comprehension of children I can testify, not only from my own observation, but from the experience of numerous teachers, such as those whose names are appended to the testimonials, on the first pages of this work. If this is not sufficient, I have to commend to the attention of the reader, the following extract from a lecture of Mr. George Combe, the distinguished phrenologist of Edinburgh, which he was so kind as to communicate to me by letter :

" I take the liberty to urge very earnestly on your attention, not only the advantage, but the necessity of introducing instruction in anatomy and physiology into popular education. The great laws of health cannot be understood, nor can their importance be appreciated without this knowledge. I do not mean that you should teach your children all the minute details of these sciences, which would be necessary if you intended them for the practice of medicine and surgery: all I desire is, that the structure of the leading organs of the body should be explained so far as to render the functions of them intelligible, and that on this knowledge should be founded a clear and practical elucidation of the laws of health. I can certify, from observation, that this instruction may be communicated to children of ten years of age, and upwards, with great success. The structure addresses their observing faculties, and an explanation of the functions is as interesting to them as a romantic story."

In treating of physiological subjects, I have unavoidably employed some technical terms, but only in cases where there was an evident advantage attending their use; but in all such cases the exact meaning of the term has been assigned it. This explanation saves the necessity of a glossary, which was appended to the first edition, and it is, therefore, omitted in the present.

It will be perceived that the present edition contains more anatomy than the former. This has arisen from the full conviction, that in order to understand the functions of an organ, its structure must first be learned. To aid in the accomplishment of this object, numerous well executed wood cuts have been introduced, alike creditable to the artist and useful to the learner.

The work is, therefore, presented to the public in its present shape, with the hope and belief, that it will subserve the cause of human knowledge and happiness.

New York, April, 1839.