Ajñāta-yakṣma, the ‘unknown sickness,’ is mentioned in the Rigveda,1 Atharvaveda,2 and Kāṭhaka Saṃhitā.3 It is referred to in connection with Rājayakṣma. Grohmann4 thinks that the two are different forms of disease, hypertrophy and atrophy, the purpose of the spell in the Rigveda being thus the removal of all disease. From the Atharvaveda5 he deduces its identity with Balāsa. Zimmer,6 however, points out that this conclusion is unjustified, leaving the disease unidentified, which seems to accord with its name. [Footnote] 1) x. 161, 1 = Av. iii. 11, 1. [Footnote] 2) vi. 127, 3. [Footnote] 3) xiii. 16. [Footnote] 4) Indische Studien, 9, 400. [Footnote] 5) vi. 127. 3. [Footnote] 6) Altindisches Leben, 377, 378. Cf. Bloomfield. Hymns of the Athar-vaveda, 342; Atharvaveda, 60; Jolly, Medicin (in Bühler's Encyclopædia), 89.