There are several routes of loss; there is always a certain amount excreted in the urine because of the endogenous metabolism of protein, the protein turnover that occur continuously in the tissues. This has not been shown to increase as a result of exercise, other than the very small amounts reported by Cathcart. Although there is individual variability in urinary N excretion, the mean estimate for men is about 37 mg N/kg body weight. The equivalent value for women might be expected to be less, because of the lower relative fat free mass, but the experimental data show little difference.

Today, healthy individuals as well as those who are chronically ill may receive medicines for long periods of time. Therefore, it behooves us to eliminate unwarranted medicine utilization. We need several approaches, such as (a) Impove and extend education about the rational use of medicines, starting in medical school and continuing throughout the practioner's career.

An educational program on rational uses of digitalis was undertaken for the house staff at a Montreal Hospital. Simply emphasizing the importance of body weight and renal function when prescribing loading and maintenance doses of digoxin reduce the incidence of toxicity in this hospital from 21.4% to 12.3 % over a 2 year period.

The clinician must develop a system of warning about high risk patient. Patients im whom drugs must be given with more than the usual degree of caution. The newborn, the child, the elderly, the pregnant woman near term, and the lactating women are easily identified. The newly pregnant or potentiall pregnant female, the patient with moderate derangement of hepatic or renal function, and the alcoholic or other drug abuser are more difficult to identify. Yet for all of these patients a simple determination of dosage by body weight will fail to produce a rational regimen for many drugs.

The life expectancy of smokers is shorter than that of non smoker. Smoking is, by a large margin, the biggest preventable cause of death, responsible for about 1 in 10 adult death in the worldwide.