But we have not yet done with the hothouses. Just beyond the egress of the South African _annexe_, another group begins with the Succulent House, holding a store of fleshy, scaly, spiky and prickly forms of the cactus and aloe tribes, having so many odd uses, as the “vegetable cows” milked three times a day in Mexico, that their juice may be fermented into the national thin tipple _pulque_, tasting like buttermilk with a dash of sulphur, while the root of another aloe yields _mezcal_ as a stronger drink. One American cactus is not so carefully cultivated as it once was to rear the cochineal insect that dyed “England’s cruel red,” now procured more cheaply from aniline dyes first made under the group of tall chimneys below Harrow Hill. In South Africa aloes grow almost as tall as chimney stacks, so it would take the British Museum dome to house them. This indeed is not the same plant as the American aloe, better distinguished as the agave, whose flowering stem may rise to the height of half a dozen men, so here we must be content with miniature specimens to fit the Succulent House. Beside this collection stands a greenhouse glowing with bloom inside panes dimmed by frosty fog; then beyond open smaller nurseries of tropical and filmy ferns. Outside, here, is supported a huge wistaria, once wreathing the walls of a conservatory now removed. Last comes, what may be visited first, as its Grecian front almost faces the main entrance, the Aroid House, describable as a chapel of ease to the Palm House, close packed with a smaller congregation of swollen greenery, sucking in the edifying moisture that congeals on the glassy walls, and blinds for a minute or two one’s spectacled eyes, suddenly brought from the atmosphere of our zone to that of the Equator. From such artificial snuggeries it seems doubly dismal to turn out into the raw air of a truly British November, in which a few forlorn roses may still be struggling to hold up their faded heads, and dank evergreens wear hardly a more cheerful aspect than the sere leaves, “last of their clan,” that flutter down to be swept off the glistening grass. And yet those representatives of another climate, so carefully gathered and preserved, give but a poor idea of the teeming wildernesses that know no change of season but from baking heat to swamping rain, their rank vegetation always glowing under the breath of a fierce spring, while decaying in everlasting autumn beneath the richest mantles, and if there be any winter it is the daily frost of paralysing heat. The tropics come more truly before us in descriptions such as one might quote from a score of eloquent travellers, for example this by an American writer, W. H. Hurlbut:--