Introduction. In 1876 a publication by the associate professor Adolph Seeligmüller from Halle (Saale) entitled “Tonische Krämpfe in willkürlich beweglichen Muskeln (Muskelhypertrophie?)” was published [1]. Because of this publication, Seeligmüller was sometimes referred to as the first person to describe myotonia congenita before Julius Thomsen [2,3]. Thomsen also published a work in 1876 under an almost identical title. In contrast to Thomsen, whose name is used as the eponym for the disease, Seeligmüller's contribution is less known today. Methods. The publications by Seeligmüller and Thomsen are compared. Earlier descriptions of the symptoms (Bell, Benedict, von Leyden) were included in the considerations, because Thomsen and Seeligmüller also referred to them. In contrast to Thomsen“s and Seeligmüller”s descriptions in 1876, these earlier described symptoms have not been recognized as a disease entity. Results. Thomsen's publication appeared shortly before Seeligmüller [1,4]. Today, however, the exact date can no longer be determined. In his publication, Seeligmüller made clear references to Thomsen's work and criticized the use of the term “ataxia muscularis” for the disease [1]. He also had different ideas about the pathogenesis of the disease. Whereas Thomsen assigned the disease to the psychoses and thought of a disease “in one half of the activity of the brain, the will” based “in the cerebrospinal system” [4]. Seeligmüller, assigned it to muscle hypertrophy and speculated on a disease of the lateral funiculus of the spinal cord with a “more difficultly mobile muscle substance” [1]. Discussion. Seeligmüller cannot be regarded as the first person to describe myotonia congenita before Thomsen. However, Adolf Strümpell already appreciated Seeligmüller's description in 1881, which was less subjective than Thomsen's interpretations. Seeligmüller“s contribution is mostly forgotten today, although he described the clinic and symptoms much more objectively shortly after Thomsen and although his assumptions about the pathogenesis were more accurate than Thomsen”s.