At a philosophical level, the union of glass with aquatic animalia feels like a fated match: on the one hand, the liquid medium; on the other, the lives lived in liquid—the artisan’s breath like the breath of God, giving organic form to what was once silica dust. There’s a metaphorical biology to glass that corresponds well with the biology of sea life. Both are keenly involved with the question of which forms are efficient and well-adapted, and thus most frequently brought into being.

The glass we buy is still: fragile and calm, content to hold forever its frozen form. But the glass of the artist is wild and molten. A hot, thick, slow-moving liquid, its primary allegiance is to gravity. It glows and blazes; it cannot be touched directly with the hands. Craftsmen spin globs of it on rods, whirling the sticky mass constantly to ensure it won’t sag. They blow into the soft glass through hollow pipes, and their breath expands it into bulbous forms. Like jellyfish, sea anemones, and the heads of hydroids, forms worked in glass tend towards the symmetric and the rounded. These are the easiest forms to produce—and the strongest.

The microscope’s bronze barrel injected horror into the natural kingdom, shocking onlookers, according to historian Isobel Armstrong, with “the gross feeding and sexual avidity of the animalcules.” Through the looking glass of the microscope, late 19th century audiences fell into a surreal new dimension, at once scientific and strange. In the case of the Hydroid series, glass gives the Lovecraftian handmaids a sensuous vitality, shaping human energies into an imitation of organic styles. Blown through hot fluid, the breath of the Blaschkas opened naturally round bubbles, forming the transparent cocoons out of which our Hydroid’s babies hatch. The centripetal force of the artist’s spinning hand gathered into thick transparent drops the solid chains of sporosacs, as well as curving the trunk of the enlarged hydranth. Note, too, the fluid lines of that model’s fleshy arms. Underwater, liquid pulls the flowing tentacle; here, the flow of the artisan’s hand pulled the liquid of the glass. Instead of sharp stops, these limbs end in miniscule clear blobs. Like nature, glass smoothes away the hard edges of her works. The liquid’s desire to minimize surface tension melts fine points into balls—the characteristic bead on the end of each tentacle clues us into that collapse.

To retain a sense of marine translucency in their imitations, the Blaschkas brushed onto their shining surfaces thin, water-soluble colors—ironically producing sea creatures that could not survive fluid contact. Even the oils on fingertips would dissolve such fragile tints. In the early 1900s, someone at Harvard transferred the models onto sturdy plaster bases; students could then hold these tiles without touching the glass.

The Blaschkas are known as lampworkers because of their miniature efforts: The rods of glass they worked with—no larger than pencils—were small enough to be heated by a gas lamp. The Hydroid is their ode to the small and the exquisite. In his youth, Leopold was apprenticed to a goldsmith and a gemcutter. In a departure from the lush organic forms of its grotesque assistants, the primary model recalls not the jelly’s tentacle but the jeweler’s hand.

This technical virtuosity is on full display in the Hydroid. Instead of pure glass, the Blaschkas rendered the soft twisting strands of Tubularia indivisa in glass-coated wire—the slight bend of the stalks produced not by liquid motion but by the crimping of the craftsman’s pliers. They threaded onto each wire the fragile bead of a hydranth, a hollow glass crown. Each thin, translucent flower reveals within an intestine of metal. Strands of pearly sporosacs float off in pairs from these heads, a twinning not present in nature but ubiquitous in contemporary earrings.

Not only does the model play on the jeweler’s repertoire of forms, it also asserts his profession’s dexterity of hand. Consider the delicate glass mane that adorns each pale hydranth. These vitreous eyelashes are vanishingly fine and totally uniform in their slenderness, evidence of the artisans’ remarkable muscular control. Repeating the same quick, disciplined motion, they achieved a shockingly consistent velocity in pulling out these strands. With a gemsetter’s surgical dexterity, the Blaschkas fused each glass hair to the belly of a hollow flower. This high risk endeavor was carried out with perfect precision—a single clumsy gesture could ruin hours of work.

Ironically, this very delicacy of detail also destroys the possibility of perfect realism. Glass melts easily and fuses without trouble: The material properties that enable the assembly of these thin hairs also require that they be placed with no possibility of overlap, lest strand dissolve into strand during annealing. The result is an object that nods to nature while being too dainty and stylized for a true appearance of natural spontaneity (compare the model’s ethereal fixity, for example, to photos of hydroids streaming freely in ocean currents).

The Hydroid delights the eye, but the body senses the artisans’ painstaking labors. Looking closely at the Hydroid, our eyes strain, hands twitch. Our backs tense. The creature is a miniature miracle. Juxtaposed with its microscopic enlargements, the Hydroid claims that the jeweler’s work continues—literally—at the level of the subvisible.

However, the Blaschkas brought to order what late 19th century viewers recognized as a dizzying, hallucinatory, bottomless progression of scale. Although they traced all four of the microscopic enlargements on Allman’s plate, they produced only two for their catalog. Viewers experience not a slide into an infinite series but rather a manageable tourist’s circuit: instructive but limited. In all three models of the Hydroid series, the jeweler’s hand tames the lush ferocity of nature.