A NOTE ON THE RHYTHM OF CHEMICAL DIFFERENTIATION IN THE AVIAN EMBRYO

A study of the non-protein nitrogen in the embryo of eight species of birds suggests that the rhythm of chemical differentiation is always the same, no matter how long the developmental period. The thanks of the writer are due to the Government Grant Committee of the Royal Society for a contribution defraying the cost of this work, and to Mr Impey, Mrs Deller, Mr Carter, and Sir Charles Walston, for help in the obtaining of the eggs used.