The Wardian case, the direct forerunner of the modern terrarium (and the inspiration for the glass aquarium), was invented by Dr. Nathaniel Bagshaw Ward (1791-1868), of London, in about 1829 after an accidental discovery inspired him. Dr Ward was a physician with a passion for botany. His personally collected herbarium amounted to 25,000 specimens. The ferns in his London garden in Wellclose Square, however, were being poisoned by London's air pollution, which consisted heavily of coal smoke and sulfuric acid. In contrast to his flagging ferns, in the bottles where Dr. Ward kept cocoons of moths and the like, he found that fern spores were germinating and growing in a bit of soil. He had a carpenter build him a closely-fitted glazed wooden case and found that ferns grown in it thrived.
Dr. Ward published his experiment and followed it up with a book in 1842, On the Growth of Plants in Closely Glazed Cases.
English botanists and commercial nurserymen had been passionately prospecting the world for new plants since the end of the 16th century, but these had to travel as seeds or corms, or as dry rhizomes and roots. But with the new Wardian cases, it was possible that tender young plants could be set on deck to benefit from daylight, but protected from salt spray. The first test of the glazed cases was made in July 1833, when Dr. Ward shipped two specially-constructed glazed cases filled with British ferns and grasses, all the way to Sydney, Australia, a voyage of several months that found the protected plants still in good condition upon arrival. Somewhat more interesting plants made the return trip: a number of Australian native species that had never survived the transportation previously. The plants arrived in good shape, after a stormy voyage around Cape Horn.
One of Dr. Ward's correspondents was William Jackson Hooker, later director of the Royal Botanic Gardens, Kew. Hooker's son Joseph Dalton Hooker was one of the first plant explorers to use the new Wardian cases, when he shipped live plants back to England from New Zealand in 1841, during the pioneering voyage of H.M.S. Erebus that circumnavigated Antarctica.
Wardian cases soon became features of stylish drawing rooms in Western Europe and the United States. In the polluted air of Victorian cities, the fern craze and the craze for growing orchids that followed owed much of their impetus to the new Wardian cases.
More importantly, the Wardian case unleashed a revolution in the mobility of commercially important plants. In Wardian cases, Robert Fortune shipped to British India 20,000 tea plants smuggled out of Shanghai, China, to begin the tea plantations of Assam. In Wardian cases the rubber tree of Brazil was shipped successfully to the heated glasshouses of Kew, then shipped on to Ceylon (Sri Lanka) and the new British territories in Malaya to start the rubber plantations. Wardian cases were thus directly responsible for breaking key geographic monopolies on the production of important agricultural goods.
Dr. Ward was always active in the Society of Apothecaries of London , of which he became Master in 1854. Until very recently, the Society managed the Chelsea Physic Garden, London, the oldest botanical garden in the U.K.. Ward was a founding member both of the Botanical Society of Edinburgh and the Royal Microscopial Society , a Fellow of the Linnean Society and a Fellow of the Royal Society.
D. E. Allen, The Victorian fern craze, 1969