Streptomycin

I am trying to establish when streptomycin was first used in Craig-y-nos. Dr Reeves has interviewed one woman who believes she was given it as part of a drug trial in the late 1940's.
Nurse Glenys Davies remembers a young woman called Mary Williams being the first in Ward 2 to receive it either in late 1950 or early 1951.

Therefore it came as a surprise to read in Clive Rowlands autobiography that he received it in the mid 1940's, though an exact date of his time in Craig-y-nos is not given.