But the occluding callus is a mass of delicate succulent cells, and offers a dainty morsel to certain insects e.g.
Wollaston discovered palladium, especially interesting for its striking property of absorbing (" occluding ") as much as 376 volumes of hydrogen at ordinary temperatures, and 643 volumes at 90 0.
Graham showed that gold is capable of occluding by volume 0.48% of hydrogen, 0.20% of nitrogen, 0.29% of carbon monoxide, and 0.16% of carbon dioxide.