Geoffrey N. Swinney & (2008) Enchanted invertebrates: Blaschka models and other simulacra in National Museums Scotland, Historical Biology, 20:1, 39-50, DOI: 10.1080/08912960701677036 - https://dx.doi.org/10.1080/08912960701677036
The German word used here is takt, usually translated as "tact" in English. The German word has several different meanings, and in some cases is translated as "subtlety" or "heartbeat". In this context "the touch" or "the feeling" is closer to the intended meaning than the usual "tact". See Takt: German to English translation on Interglot.
Schultes, Richard Evans; Davis, William A.; Burger, Hillel (1982). The Glass Flowers at Harvard. New York: Dutton. Excerpt available at: "The Fragile Beauty of Harvard's Glass Flowers". The Journal of Antiques and Collectibles. February 2004. Archived from the original on 2016-04-11. Retrieved 2015-06-10.
Schultes, Richard Evans; Davis, William A.; Burger, Hillel (1982). The Glass Flowers at Harvard. New York: Dutton. Excerpt available at: "The Fragile Beauty of Harvard's Glass Flowers". The Journal of Antiques and Collectibles. February 2004. Archived from the original on 2016-04-11. Retrieved 2015-06-10.
