Leonardo’s Mountain of Clams and the Diet of Worms by Stephen Jay Gould

plants . . . Literally millions of plants were ferried to and fro in Wardian cases, [and] they eventually succeeded in establishing tea as a cash-crop in India (from China) and rubber in Malaya (fromSouth America), thus adding two valuable new commodities to the British Empire’s resources. Kew’s Wardian cases were probably one of the best investments the British Government has ever made, and in fact they were only very recently superseded by the use of polythene bags.
    On a humbler, yet massive, scale, Wardian cases also became a fixture in almost every British home of approved taste. Althoughmany kinds of plants could be grown in such cases, a passion for ferns—so spectacular as a social fad that the epidemic even received a latinate description as Pteridomania, or the fern craze—swept Britain in the 1840s. When this mania inevitably subsided, the technology of Wardian cases remained, ready to be utilized for the next enthusiastic bout of rustic adornment—the aquarium craze ofthe 1850s.
    All fads, however brightly they may burn for the moment, seem to run their appointed course in relatively short order. The aquarium craze dominated amateur interest in natural history during the 1850s, but quickly subsided during the next decade. By 1868, another popular naturalist, the Reverend J. G. Wood, could write:
    Some years ago, a complete aquarium mania ran through the country.Every one must needs have an aquarium, either of sea or fresh water, the former being preferred . . . The fashionable lady had magnificent plate-glass aquaria in her drawing room, and the schoolboy managed to keep an aquarium of lesser pretensions in his study . . . The feeling, however, was like a hothouse plant, very luxuriant under artificial conditions, but failing when deprived of externalassistance . . . In due course of time, nine out of every ten aquaria were abandoned . . . To all appearance the aquarium fever had run its course, never again to appear, like hundreds of similar epidemics.
    Even the most ephemeral episode of public fascination teaches us many lessons about the social and ideological context of all scientific movements. We have already seen how the aquariumcraze relied upon chemical discoveries, a philosophical notion about natural balances, a social system that supported a substantial class of domestic servants in wealthy homes, and the development of a technology first exploited in a previous craze for ferns. Further reading reveals other important ties to political and technological history, most notably the necessary repeal, in 1845, of the heavytax that had been levied upon glass. Gosse’s “how to” book of 1856, The Aquarium: An Unveiling of the Wonders of the Deep Sea , exposes the social or technological solution to a number of practical problems that would probably not occur to a casual reader today. How, for example, could an urban enthusiast get sea water for his home aquarium? Gosse advises:
    In London, sea-water may be easily obtainedby giving a trifling fee to the master or steward of any of the steamers that ply beyond the mouth of the Thames, charging him to dip it in the clear open sea, beyond the reach of rivers. I have been in the habit of having a twenty gallon cask filled for me, for which I give a couple of shillings.
    And how can specimens be safely transported to town with adequate speed? By fast train, of course.Gosse writes:
    The more brief the period during which the specimens are in transitu the better. Hence they should be always forwarded per mail train, and either be received at the terminus by the owner, or else be directed “To be forwarded immediately by special messenger.” The additional expense of this precaution is very small, and it may preserve half the collection from death through longconfinement.
    Any social movement must illuminate its own time, so we should scarcely be surprised by such enlightenment from the aquarium craze of the 1850s. But what can we say about