contagium

From Latin contagium (“contagion”).

contagium (plural contagia)

1. (archaic) contagion; contagious matter [ca. 1870—1910]
   • 1865, John Simon, “Minutes of Evidence Taken Before the Cattle Plague Commissioners”, in Report on the Origin, Propagation, Nature, and Treatment of the Cattle Plague, published 1866, page 42:

     And its escape [from certain diseases] is an approximative proof that, at least for those ten years, no contagium of measles, “nor any contagium of scarlet fever, nor any contagium of small-pox, had arisen spontaneously" within its limits.

   • 1901 December 20, H. Watkins-Pitchford, “Rinderpest”, in The Agricultural Journal and Mining Record‎, volume 4, number 21, pages 641–642:

     That this in fact was the case was ascertained by Dr. Edington, who, by adding a large percentage (33 per cent.) of glycerine to the gall taken from a rinderpest beast, was able to show that by such contact the infective power of bile was as effectually destroyed as was the contagium of blood.

From contingo (“to contact; contaminate”) +‎ -ium, from con- (“with”) +‎ tango (“to touch”). More precisely, built on the root of the verb (see Proto-Indo-European *teh₂g-) and so lacks the nasal infix found in the verb's present stem; compare contāgiō and contāminō.

contāgium n (genitive contāgiī or contāgī); second declension

1. contact, touching

   Synonyms: contāctus, contāgiō

2. contagion

   Synonyms: contāctus, contāminātiō

Second-declension noun (neuter).

¹Found in older Latin (until the Augustan Age).

• contāgiō
• contingō

• “contagium”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “contagium”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• contagium in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• contagium in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.