Slide showing five pairs of equations relating to genetic combinations of X and Y chromosomes. Slide shows five pairs of equations relating to genetic combinations of X and Y chromosomes. Pair one are entitled 'Strong [female]' and 'Transformed X Y [male]'. Pair two are entitled '[male]' and '[female]'. Pair three are entitled '[female]' and '[female]'. Text follows: 'The result is thus in keeping with the experimental findings, 2 [females] [female]: 1 [male]. The first mentioned of these female types is the one that is of particular interest here. It is crossed with a strong male.' Pair four are entitled 'Weak Y [female]' and 'Strong [male]'. Pair five are entitled '[male] and '[female]'. Handwritten in black ink on tape at top of rear pane '24'. Late 19th to early 20th century