Letter from E Arnold Carmichael, Medical Research Council, Research Unit, National Hospital, Queen Square WC1, to A V Hill, Dept of Physiology, University College WC1 Has heard from army authorities that the Belgian army is unwilling to release Pirenne - notes that Bridadier Ling is taking the matter up but would be grateful if Hill could also lend support - 'we are very short of men working on vision and it would be most valuable to have his services'. 16 March 1942