Louis Pasteur’s memoir "is a very able and convincing one" ["Mémoire sur les corpuscles organisés qui existent dans l’atmosphère", Ann. Sci. Nat. (Zool.) 3d ser. 16 (1861): 5–98].

E. A. Parkes informs him there will be difficulty about the Army returns [on CD’s Query to Army surgeons, see Freeman, Works of Charles Darwin, p. 111] owing to official obstructions by Director General. [Enclosed letter from Parkes to GB says that the Director General does not think that Army surgeons could be asked to collect information systematically for CD, but perhaps some informal, voluntary arrangement could be made.]

Asks for an order to buy a CD photograph for Mr Tait.