I have named this work a Dictionary of "Materia Medica" because no other name would have been intelligible. But the name, nevertheless, in homœopathy, is somewhat of a misnomer. We are dealing with forces which, though derived from materials, are anything but "material" in the common acceptation of the word. Our agents are forces of a higher order than any known to Old Physic, and it is important that homœopathists should know them as such. Homœopathy is from first to last an art of individualising. We have to individualise patients, and individualise remedies. However convenient it is to think of remedies in connection with the diseases in the treatment of which they are most frequently called for, it must never be forgotten that this is a convenience and nothing more. To allow our conception of our remedies to be limited by any list of nosological terms is to accept again the mental fetters of old-school therapeutics. To understand and utilise our remedies to the fullest extent, we must know them as powers ready to serve us in any case, no matter what the name of the disease may be, when the indications for them come to the front. And we must be prepared to find these powers hidden in common articles of food and drink, which we are constantly taking into our bodies in large quantities with complete impunity; and even in the tissues and secretions, morbid and healthy, of our bodies themselves. My object in the Dictionary has been to so present the picture of each remedy that it may be at once recognised and distinguished from any other by those who consult its pages. In doing this I have considered first those points which seem to me to have a practical bearing; points which have seemed of academic interest only I have left in the main to other works.