When cotton fibre is placed in zinc chloride swelling agent (62°), the primary wall of the fibre splits to collars of approximately constant width-to-length ratio. Also, it may split to form spirals of approximately constant helix angle. The tested fibre length includes both types of split, but in different proportions. The secondary wall bulges out at the separated regions, as compared to the primary wall, while, for collar forms, it splits the secondary wall, which bulges remarkably, forming beads or string of pearls. It was found, for the cotton examined, that the number of beads formed and the bundle strength (Pressly index) are well correlated. The strength tends to be high for a high number of beads and the correlation coefficient r=0.885, highly significant at the 5per thousand level.