Sentence:  In criticism of the <WSD>latter</WSD> 's views , his conclusions were based upon dog lung injection studies in which all of the vascular channels were first filled with a solution under pressure and then were injected with various sized colored particles designed to stop at the arteriolar level . 
Meaning of the word marked with <WSD> tags:  referring to the second of two things or persons mentioned (or the last one or ones of several)