Sentence:  For the albumin method , equal volumes of 30 % bovine albumin , sample and 2 % cells suspended in saline were allowed to stand at room temperature for 1 hr and then were centrifuged at 1000 rpm for 1 <WSD>min</WSD> . 
Meaning of the word marked with <WSD> tags:  a unit of time equal to 60 seconds or 1/60th of an hour