Fig. 2. Parallel arrangement of an experiment for mammal and plant, illustrating Bernard's vision that the essence of life, which he thought was embodied in the protoplasm, was shared and comparable across kingdoms. Reproduced from Bernard C: Leçons sur les phénomènes de la vie commun aux animaux et aux végétaux, Librairie J-B Baillière et Fils, 1878. Available in the public domain at http://books.google.com/.