The following paper attends to the metaphorics of sclerosis across the poetry, prose, and criticism of the twentieth-century Yiddish writer Yankev Glatshteyn. I first turn my attention to his 1920 poem, "Arteriosclerosis," which takes as its subject an elderly man whose slow death by vascular constriction perfuses into the form and rhythm of the poem. The text has received scant scholarly attention, yet it stands as a performative intervention into modernist poetics and the development of Yiddish free verse. Furthermore, as my reading shows, this poem is also a hermeneutic key to Glatshteyn's 1940 novel, Ven Yash iz gekumen. Although Glatshteyn is not known as a particularly sanguine writer or as a writer of disease, the following paper demonstrates the centrality of the motif of sclerosis across his oeuvre. Indeed, sclerosis reveals what I call his "poetics of deformation," a modernist aesthetic that is simultaneously generative and incapacitating.