If the carotid artery should tire out and not be able to perform its duty the brain would tire out also, and cease to operate. Should the descending aorta come to a halt from any cause, all parts of the body depending upon that vessel would suffer a total loss of blood supply. Equally so with any other principal artery of limb or body, all mark a failure equal to the suspended supply. The parts and principles of the human body depending upon the heart are numerous beyond computation. Every expulsive stroke of the heart throws into line armed and equipped for duty thousands and millions of operators, whose duties are to inspect, repair injuries and construct anew if need be from the crown of the head to the sole of the foot. With the best eye of reason we see but dimly into the breast of man which contains the heart, the wonder of man and the secret of life. I have given these bulky descriptions of the forest and ocean to prepare the mind of man to begin the inspection of the machinery that has constructed the body of which he is the indweller. If we cannot swallow all, we can taste. FROM NECK TO HEART. The hearts of all animals should call the most careful attention of the student of nature. He finds in it the first act of life; from it go all parts or by it all parts of the body are made, and the student of nature soon learns that at the heart he finds the first evidence of the power of life to continue and give useful shape to matter. Its first work is to complete itself in material form with necessary chambers to hold blood and with tubes to convey to all places of need. He sees vessels leaving the heart to form brain, lungs, liver, trunk and limbs, and with each and all he can see the nerves of motion, sensation, nutrition, the voluntary and involuntary--all working in perfect harmony and content to do their part in the economy of life. Without that union in action a confusion will show in form of abnormality which is known as disease. On its work all nerves do depend for force and strength to build and renovate the body in all its bones, muscles and nerves--thus all channels to and from the heart must be cleared from all hindrance. No nerve can do its part unless it be well nourished. If not it will fail to execute its part for want of power--for by it all blood must move. These nerves are found in plexuses in all parts of the body; they are abundant in the skin, fascia, muscle, lymphatics and all organs great and small. The Osteopath must know or learn that no infringement can be tolerated in any part. Nature's demands are surely absolute, and require that the last farthing shall be paid in full. Now for a start--we will explore the neck; here we have the great and small occipital and the cervical group all receiving from the brain and feeding parts below. Thus we must stop at the neck and read the lessons that can be found there, and learn them well; or we will find that we will not be able to meet diseases only to be defeated.