Few things make a person feel as helpless as a hospital bed, and few objects seem as smugly in charge as the thermometer. John B. Colwell's "To a Hospital Thermometer" turns that imbalance into comedy. Its speaker, evidently a patient, can't talk back to the nurse or the doctor, so he talks back to the next best thing: the little glass tube under his tongue. The poem is a lighthearted tirade, and its central idea is that when you have lost control of your body and your dignity, a joke is a way of taking some of both back.
The first thing to notice is who the speaker addresses. A poem "to" an object is a familiar move, and it works by pretending the object is a person. Colwell commits to the pretense completely. The thermometer is "plumb full of 'sass,'" it is "chuck'ling, chort'ling, grinning, smug," and the speaker demands, "Where'd you get your license, lug?" A lug is a clumsy lout, so the delicate instrument is demoted to a street-corner bully, and "license" suggests the thermometer is some kind of unauthorized lawman. The humor lies in the mismatch between a fragile "little, shining, piece of glass" and the swagger the speaker pins on it.
That swagger is credited to the thermometer's protector. In the second stanza it sits "safe beneath the nurse's thumb," and the speaker admits that nobody in his position "can speak his thoughts" while it is in his mouth. The joke is practical as well as figurative: you really can't say much with a thermometer under your tongue. The nurse's brisk imagined command, "Settle down old boy, you're stung!", puts the patient in his place with a pun, since "stung" suggests both caught out and jabbed. The speaker is outranked on every side, which is what makes his bluster funny.
The third stanza escalates the accusations. The thermometer is a "sleuth," doing "detective stuff," and the speaker asks, "What you huntin' in my mouth?" The reading of body temperature is recast as a criminal investigation, and the patient is the suspect. His nervous questions, "Think I'm balmy? Goin' South?", use slang for being crazy and for dying or declining, and they hint that beneath the jokes there may be a flicker of real worry. Judging by the tone, though, that worry stays at the edge; the poem would rather laugh than brood.
The sound of the poem does much of this work. It runs in short, bouncing lines with four stressed beats, which gives it the feel of a nursery rhyme or a music-hall patter song. Every pair of lines rhymes in couplets (glass/sass, thumb/gum, tongue/stung), and the rhymes are deliberately goofy. "By gum!" and "lug" belong to the casual speech of an earlier, folksier way of talking, and the dropped letters in "huntin'" and the awkwardly split "chuck'ling, chort'ling" make the lines sound spoken aloud, as though the patient is muttering between breaths. The rhythm keeps stumbling forward, never quite dignified, which suits a man in a hospital gown.
The last stanza shifts the poem's angle in a clever way. The speaker concedes, "I may fail to grade 'elect,'" meaning he may not be a prize specimen, but insists, "I keep my self-respect." Then he delivers his parting shot: the thermometer, for all its power, spends its off-hours soaking "in alcohol / Winter, summer, springtime, fall." The pun on "steep" is the neatest in the poem. The thermometer is pickled, a drunk, and the final line's list of seasons makes the sentence feel endless, as if the poor instrument were stuck in a dull routine. The speaker's revenge is to notice that the apparent authority figure has no life at all outside its jar.
What makes the poem worth reading is how cheerfully it handles an experience that is usually miserable. It doesn't deny that the patient is powerless; it admits as much. But by giving a lump of glass a personality, then cutting that personality down to size, it lets a vulnerable speaker end the poem standing, slightly smug himself. It is a small, funny piece, and its lesson is a sturdy one: humor can be a patient's best medicine.