A second work, of somewhat similar character, is entitled _Subtilitatum diversarumque creaturarum libri novem_. This is clearly a compilation, and numerous passages in it can be traced to such sources as Pliny, Walafrid Strabus, Marbod, Macer, the Physiologus, Isidore Hispalensis, Constantine the African, and the _Regimen Sanitatis Salerni_, only the last three of which exerted a traceable influence on the genuine works of our authoress. Nevertheless this _Liber subtilitatum_ was early printed as Hildegard’s work, along with a treatise attributed with as little justification to another woman writer, Trotula, one of the ladies of Salerno, whose name was also a household word in the Middle Ages, and was freely attached to medical writings with which she had little or nothing to do.[22] It is true that Hildegard’s contemporary biographer, the monk Theodoric, assures us that she had written _De natura hominis et elementorum, diversarumque creaturarum_,[23] but there is nothing to suggest that the _Liber subtilitatum_ is intended thereby. The modern scholars Daremberg and Reuss have edited the _Liber subtilitatum_ as Hildegard’s composition,[24] and the work attracted the attention of Virchow,[25] but notwithstanding the authority of these names, the objections which apply to the genuineness of the _Causae et curae_ are also valid here: (_a_) The _Liber subtilitatum_ is not included in the Wiesbaden Codex A. (_b_) The phrase _De natura hominis et elementorum diversarumque creaturarum_, used by Theodoric as a description and by Reuss as a title,[26] would lead one to expect great emphasis on the nature of the elements and their entry into the human frame. Such emphasis is not, in fact, discoverable in the _Liber subtilitatum_, which, moreover, does not treat of human anatomy or physiology. (_c_) On the other hand, the genuine _Liber divinorum operum simplicis hominis_ does lay stress on these points. This is possibly therefore the work to which Theodoric refers, and to it his description certainly applies well. (_d_) As in the _Causae et curae_, there are linguistic difficulties that prevent us attributing the _Liber subtilitatum_ to Hildegard. Such, for instance, is the number of Germanisms as well as the marked difference from the style and method of her acknowledged work. (_e_) There are statements in the _Liber subtilitatum_ that can scarcely be attributed to our authoress. Having largely explored the Rhine basin, and corresponding constantly with writers beyond the Alps, how could she possibly derive all rivers, Rhine and Danube, Meuse and Moselle, Nahe and Glan, from the same lake (of Constance) as does the author of the _Liber subtilitatum_?[27]