Ring Irish College case: TAF (acid-fast bacilli) opacity photographs

Four b/w photographs (and four negatives), with associated correspondence between Dr O'Brien and Major H C Brown (Wellcome Bureau of Scientific Research). Includes letter (8 December, 1937) from O'Brien to Sir Henry Dale.

O'Brien to Brown (19 August, 1937): "What we should like to demonstrate to the Jury by photographs is that:
A. The opacity of all three is about the same when they are shaken up.
B. If they are allowed to sediment, the rate of sedimentation is widely different and eventually, after some days, one ends with the whole of the tubercle bacilli deposited on the floor in an extremely thin layer, whereas the TAF is still flocculent matter from half-an-inch to an inch high."

The photographs show the bottles immediately after shaking, after one day, after four days, and after six days.

1937

1 file 4 x b/w photographs (each approx 110 x 150mm), plus 4 negatives, plus 7 sheets.

Copyright assigned to the Wellcome Trust

Copy of 1937 opacity photograph captioned 'After allowing to settle for 4 days' available on Wellcome Images. Image number L0051194.