In reply to your letter of April 23rd, the papers by Professor Karl Pearson on Mathematical Contributions to the Theory of Evolution have been published in the "Philosophical Transactions [of the Royal Society]", but the Separate Numbers in which they appeared are out of print. They could be consulted in the volumes of the Transactions where they appeared.
I am, faithfully yours,
Robt [Robert] Harrison
Assistant Secretary R.S. [Royal Society]'.