My "Manual of Diet and Regimen" which appeared in 1864, having run through two editions in its first year, I published a third and revised edition in January, 1865. This has long been out of print, and, as the demand for the Manual did not decrease, I have been repeatedly urged to prepare a fourth edition. After many delays, from the interruption of other professional work, I have, at last, re-written the book, adding much new matter and incorporating several contributions, which I have published from time to time, on subjects relating to the preservation of health. I hope it will be found that I have thus materially increased the usefulness of the work without adding inconveniently to its length. My object and endeavour has been to produce a small book founded upon accurate scientific data but essentially practical: a book from which a doctor may refresh his memory, and at the same time one which he may safely place in the hands of his patients, to enlighten them on some of those important points which ought to be understood by the non-professional, and to teach them how vast and intricate is the science and art of rational medicine. Thus to make them more intelligent patients, and in so doing to remove some of the doctor's difficulties in healing them when they are sick, and when they are well to strengthen his hands in the preservation of their health.

It gives me great pleasure to be able to renew the thanks I expressed in 1864 to my friend Mr. Farrants, at that time President of the Microscopical Society, for the valuable assistance I have so frequently received from his remarkable analytical and arithmetical talents.