The use of cod liver oil as a prophylactic and therapeutic agent in the treatment of patients with rickets, while widespread and generally satisfactory, is being somewhat supplanted by irradiated ergosterol. It was felt desirable to study a controlled group of infants, some of whom were given cod liver oil, some irradiated ergosterol and others cod liver oil and irradiated ergosterol, keeping a number to whom no antirachitic agent was given.
A great many of the present observations on the therapeutic and prophylactic value of irradiated ergosterol are based on experiments on laboratory animals, and these reports are made still less accurate in that the dosage of irradiated ergosterol is stated in milligrams, though it is well known that different batches of irradiated ergosterol vary tremendously in the amount of vitamin D contained.
The only satisfactory way to make comparative evaluations of cod liver oil and irradiated ergosterol as antirachitic
BARNES DJ, BRADY MJ, JAMES EM. THE COMPARATIVE VALUE OF IRRADIATED ERGOSTEROL AND COD LIVER OIL AS A PROPHYLACTIC ANTIRACHITIC AGENT WHEN GIVEN IN EQUIVALENT DOSAGE ACCORDING TO RAT UNITS OF VITAMIN D. Am J Dis Child. 1930;39(1):45-58. doi:10.1001/archpedi.1930.01930130057005