Letter from Douglas Rayner Hartree, on a paper 'A theoretical study of the influence of diffusion and chemical reaction velocity on the rate of exchange of carbon monoxide and oxygen between the red blood corpuscle and the surrounding fluid' by Phyllis Nicolson and Francis John Worsley Roughton, to D C Martin Paper reference code: B38 Hartree finds the mathematical arguments and numerical methods 'satisfactory' however, suggests the presentation could be improved. Written at 21 Bentley Road, Cambridge [England]. [Published in Proceedings B, 1951]. Endorsed on recto as received 18 September 1950. 17 September 1950