He prepared his Medulla Theologiae (The Marrow of Theology), a manual of Calvinistic doctrine, for his students. Ames was much influenced in terms of method by Ramism, and opposed the residual teaching of Aristotle.Willem Frijhoff, Marijke Spies, Dutch Culture in a European Perspective (2004), p. 286-7. His De Conscientia, ejus Jure et Casibus (1632), an attempt to bring Christian ethics into clear relation with particular cases of conduct and of conscience, was a new thing in Protestantism.
