He is surveying the literature on the struggle for existence among pasture plants. Asks CD for the "many cases on record" of changed relations among plants under slightly changed conditions alluded to in the Origin. [See M. T. Masters, J. B. Lawes and J. M. Gilbert "Agricultural, botanical, and chemical results of experiments on the mixed herbage of permanent meadow, conducted for more than twenty years in succession on the same land (pt 2, The botanical results)", Philos. Trans. R. Soc. Lond. 173 (1883): 1181–413.]