Human growth hormone, prepared by the glacial acetic-acid extraction method from pituitaries obtained at autopsy (1), was found to be continuously effective and well tolerated when administered by intramuscular injection to a 17-year-old male pituitary dwarf for a period of ten months. A dosage of 1 milligram twice a week produced an initial stimulation of growth, but was probably insufficient to sustain an optimal growth rate. Two milligrams three times a week was effective for the last seven months of the treatment period, producing a growth rate of 2.6 inches per year as compared to 0.5 inch per year for the 1^-year period before treatment (Fig. 1). The total increase in height during the ten months of growth hormone therapy was 2.1 inches, representing a growth rate slightly greater than that of a normal child of the same height. The concentration of inorganic phosphorus in the serum increased from 3.6 mg. to 6.0 mg. per 100 ml. during treatment, and alkaline phosphatase activity rose from 4.2 to 6.0 Bodansky units. The increase in the levels of serum inorganic phosphorus and alkaline phosphatase to values characteristic for growing children was supportive evidence of the growth hormone activity. There are no changes in these levels when animal growth hormone preparations are used in pituitary dwarfs, even for prolonged periods (2).

The immature state of the penis and testes was not affected by the treatment, and no pubic or axillary hair appeared. There was no advance in bone age during the period of growth hormone therapy. There was an increase in hemoglobin concentration (to 98 per cent) compared to earlier values (86 per cent), and possibly in red blood cell count. No redness, tenderness, or induration developed at the sites of injection nor were there any generalized allergic reactions. No eosinophils were noted in a differential white cell count after eight months of treatment. The concentration of