It is evident that this can be done only by preventing, or removing as far as possible, the predisposing causes. A glance at the list of these shows that much depends upon the cooperation of the patient by regulating his habits of life. Physical and mental overstrain must be avoided, deleterious habits, such as the use of intoxicants or narcotics given up. Much can be done by osteopathy to eliminate the effects of these upon the organism. Cardio-vascular and renal symptoms are very important and should be watched for in order that early treatment may check the process initiated. To this end the patient’s habits and diet must be regulated and treatment instituted to relieve toxicity and promote elimination. Lesions must be corrected, special attention being given to the lower dorsal that affect the kidneys, the upper dorsal that affect blood pressure, and both the upper cervical and upper dorsal that affect the blood supply and nutrition of the brain. =Arteriosclerotic Dementia.=—This is a mental enfeeblement arising sometimes in the fourth, but chiefly in the fifth, decade of life, and associated with symptoms of arterial hardening. The cause is arteriosclerosis, which may be secondary to some form of nephritis. The arterial hardening may be general or may be confined to the arteries of the cerebrum. It is likely that the arterioles supplying the cortical cells are especially involved in an atheromatous condition. The disease is organic, chronic and progressive. Hemorrhage, embolism, or thrombosis may occur, producing focal lesions and areas of softening, with hemiplegia, aphasia, etc. The earliest symptoms may be headaches and dizziness. The blood pressure is usually found to be high but not invariably. An atheromatosis may be present in some one of the palpable peripheral arteries, such as the radials. Further symptoms on the physical side are quick fatigue, loss of energy, numbness and paresthesias of the extremities, and somnolence in the daytime or perhaps insomnia at night. Strokes may occur, usually slight and temporary, probably due to spasm in a degenerating artery or perhaps to serous effusion. Toxic symptoms appear, due to disorder in kidneys, liver, and other organs. Epileptiform seizures are possible. Mentally the patient shows impairment of memory, and perhaps some confusion and hallucinations. Rarely stupor occurs. He may be agitated and irritable or melancholy and depressed. Suspicious and persecutory ideas of the paranoid type may appear; also hypochondriacal ideas.