inoculate: (horticulture) to insert a plant bud as a graft into another plant; (medicine) to insert a disease organism into the body by puncturing the skin, or into a culture medium using a needle; (medicine) to inject a vaccine
In May 1796, Edward Jenner found a young dairymaid, Sarah Nelms, who had fresh cowpox lesions on her hands and arms. On May 14, 1796, using matter from Nelms’ lesions, he inoculated an 8-year-old boy, James Phipps. Subsequently, the boy developed mild fever and discomfort in the axillae. Nine days after the procedure he felt cold and had lost his appetite, but on the next day he was much better. In July 1796, Jenner inoculated the boy again, this time with matter from a fresh smallpox lesion. No disease developed, and Jenner concluded that protection was complete.
Stefan Riedel “Edward Jenner and the history of smallpox and vaccination” (2005)
That’s Edward Jenner, the inventor of vaccination, performing an experiment that would be difficult to get past an ethics committee these days.
The Oxford English Dictionary has citations for inoculate, meaning to graft the bud of one plant into the bark of another, going back as far as the fifteenth century. Its first citation with the sense of inserting disease organisms into the skin through a wound or puncture dates from 1722, and refers to the disease smallpox—a small quantity of fluid or scab from a smallpox pustule was rubbed into a skin incision.
Why were people rubbing each other with smallpox? Because it was understood to be a way of producing a mild infection, which people usually survived, and after which they developed immunity to subsequent infection with the disease, which carried a mortality of 30%. The practice was introduced to England in 1721 by Lady Mary Wortley Montagu, who had encountered it in Constantinople. (To demonstrate its efficacy, this inoculation was carried out on several imprisoned criminals and abandoned children, who were later exposed to smallpox without ill-effect. Another one you’d struggle to get past an ethics committee nowadays, I feel.) The practice was introduced to North America by an African whose slave-name was Onesimus, and it was deployed during the Boston smallpox epidemic of 1721. Another name for this practice was variolation, from variola, the medical Latin name for smallpox, which derives from Latin variola, “pustule”.
But variolation was not without risk—about 1% of those thus inoculated died. At which point, enter Jenner, and the observation that dairy workers who became infected with cowpox, a mild disease they acquired from cattle, were subsequently immune to smallpox. Using the technique of inoculation, Jenner was able to use cowpox to produce a mild case of a mild disease, which then conferred immunity from smallpox. In the medical Latin of the time, cowpox was called variolæ vaccinæ (“cow pustules”), from Latin vacca, “cow”. In English, this spawned the adjective vaccine (originally pronounced to rhyme with sign, not seen), “pertaining to cowpox”. Which in turn quickly gave rise to the noun vaccine, the stuff that was introduced into the skin by the process of vaccination. And so both inoculation and vaccination went on to become general terms for the process of injecting a substance in order to provoke immunity to an infectious disease. About a century later they were joined by immunization, and the three words have fought a battle for supremacy every since.
When I was a kid in Scotland in the 1960s, we received the limited repertoire of inoculations then on offer; but nowadays we elderly folk are invited for vaccinations. That shift in usage is reflected in the Google Ngram for the three competing terms, with inoculation taking a fairly recent dive in popularity.
In the days before smallpox was eliminated from the world, routine childhood inoculations included a descendant of Jenner’s original vaccine—in the UK, a dried extract of lymph taken from a calf infected with cowpox. This was mixed with a diluent and then carefully pricked into the skin of the recipient using a bifurcated needle charged with a bead of the vaccine, in what amounted to a medicalized reenactment of the original process of variolation. You can see the whole kit (lymph, diluent, needle) at the head of this post. The bifurcated needle was wielded several times, producing a small ring of inoculations, which initially formed up into pustules and then matured into a round, indented white scar, still visible on the upper arms of those of us of a Certain Age.
The word inoculate derives from the Latin inoculare, which in turn derives from the prefix in-, “into”, and the noun oculus, which usually meant “eye” but did double duty as an occasional word for “plant bud”. So inoculare meant “to insert a plant bud”, which is the original meaning of inoculate, too. There are no other remotely common words in English derived from this specialist meaning of oculus, and that may be part of the reason that people often associate inoculate with the unrelated word innocuous (derived from Latin in-, on this occasion meaning “not”, and nocuus “harmful”), and want to give it a double “n”. A Google search for the erroneous spelling innoculate produces 800,000 hits; innoculation about the same number, including an embarrassing 38 entries in the on-line catalogue of the Wellcome Collection of medical books.
A person who performs inoculation is an inoculator, which has a very rare feminine form inoculatrix. The stuff that is inoculated is the inoculant or the inoculum.
The remaining oculus words relate to the Latin meaning “eye”, which has the diminutive ocellus, which is applied to the primitive eyes of molluscs and other creatures, and is also the name for a single facet of the compound eyes of insects. Something biocellate is marked with two eye-spots, like a butterfly’s wings. Anatomical structure that support an eye, such as the horns of a snail, are oculiferous. The adjective ocular means “pertaining to an eye”, something possessing eyes is oculate, and a person who studies and understands eyes is an oculist practising oculism (but an ocularist is a person who makes glass eyes). Deocular is a rare old word for “blind”.
Doctors have a whole collection of eye-related words that need not detain us for long. Examples include supraocular (“above the eye”), periocular (“around the eye”) and the grim exoculation (“removal of an eye”), but there are many more.
Monocular once meant “having one eye”, but that task has largely been taken over by monoculous, leaving monocular to deal with “pertaining to one eye”. A monocule is a creature with only one eye; a monoculist, monoculus or monoculite is a one-eyed person. And of course a monocle is a single eye-glass.
Binocular has similarly surrendered the meaning “having two eyes” to binoculate, reserving “pertaining to two eyes” for its own use. A binocle is an opera glass—a little pair of binoculars on a stick that can be used to observe the action on-stage.
For creatures with greater numbers of eyes than two, we have triocular (three), senocular (six), octonocular (eight), centoculated (one hundred, reserved for the mythical all-seeing giant Argus Panoptes) and the noncommittal multiocular (many).
The three-eyed option pertains pretty much exclusively to New Zealand’s tuatara, a reptile possessing a remnant “parietal eye” on the top of its head. So triocular isn’t a word you see every day. Which is perhaps why, when science-fiction writer Larry Niven introduced a race of three-eyed aliens to his Known Space universe in 1968, in a short story entitled “There Is A Tide”, he instead used the word trinocular to describe them—a perfectly reasonable construction. In the later Known Space novel Ringworld (1970), the race is accordingly called the Trinocs.
But it’s not just a science-fiction word, because back in 1960 the trinocular microscope had been invented. No, you don’t need to be a Trinoc to use it—it consists of a binocular microscope with a camera attached, so that you can photograph what you’re looking at.