baguette)". Having spoken, he once more takes the rod in hand to test it. It does not move. Horrified, for now there was no longer any doubt that Satan was the cause of its movements, the man makes the sign of the cross and runs away. But he had hardly gone more than two or three hundred paces when the thought strikes him: Is it really true that the branch will no longer move for him? He throws a coin to the ground, cuts a branch from a bush nearby, and is overjoyed when he notes how it dips down toward the money.
Another example is to be found in a report of the well-known physicist, Ritter[27], of Munich, which appeared during the early part of the 19th century. Ritter, a man with a bent for natural philosophy and metaphysics, describes an instrument which was to replace the divining rod, and which he called "balancier." It was simple enough, consisting of a metal strip that was balanced horizontally upon a pivot, and was supposed to be put into motion in the presence of metals. Ritter used this instrument in his numerous experiments with the Italian Campetti, a man who had achieved a measure of fame in Europe for his ability to discover springs and metals by the use of the divining rod. Carrying the "balancier" on the tip of the middle finger of his left hand, Campetti—whose integrity one cannot cavil at—had to touch repeatedly a plate of zinc or pewter, and had to count aloud the number of touches he made. The following curious law was found to obtain (that was probably suggested to the subject by Ritter without his being aware of it): with the first contact the "balancier" turns to the left, with the second to the right, and with the third it remains at rest. At 4 it turns once more to the left, at 5 to the right, at 6 it remains at rest, etc. It remained immovable only at the so-called trigonal numbers (3, 6, 9, 15, 21, etc.). Ritter tells us that when Campetti did not really count or did not think of the number, then it would not have any influence whatever upon the action of the instrument. This Ritter ascribes to the agency of electricity (which in the 18th and 19th centuries was made to play very much the same
rôle that Satan had played in the 16th and 17th centuries).
The similarity of these two cases and that of Mr. Schillings is evident. When the questioner of the horse and the bearers of the "balancier" and of the divining rod are confident of success, they succeed. When they do not expect success, they fail.
[V] The French investigators Vaschide and Rousseau make a reference to this case, and mistakenly state the number of signals as 1500 instead of 115[30]. Ettlinger[31]
takes over this wrong figure and makes the additional mistake of assuming that the reference is to an original investigation made by the two Frenchmen.
[W] All told, there are hardly more than half dozen experimental investigations of the color-sense in mammals,—to speak only of these. Three of them deserve especial mention. One, the work of the American, Kinnaman,[33] on two Rhesus monkeys. Then a brief but careful piece of work by Himstedt and Nagel.[34] These two investigators were able to determine that their trained poodle could distinguish red of any tone or shade from the other colors, and from Professor Nagel I learned that later the tests were extended and the same was shown to be true concerning the blue and the green. And finally there is an investigation which hitherto has been known only from a reference which Professor Dahl,[35] the investigator, himself makes. The work is on a monkey, Cercopithecus (Chlorocebus) griseoviridis Desm. (Professor Dahl has kindly allowed me to look over the records of the experiments. He intends to publish the monograph at an early date.)
All of these investigators arrive at the conclusion that the animals tested by them possess color-sense. The monkey last-mentioned shows one peculiarity: it was unable to distinguish a saturated blue from the black. It will require further tests to clear this up.
[X] There is no justification for the wide-spread belief that the horse which on account of the greater size of his eye (more correctly, on account of the greater focal distance) receives larger retinal images of objects than does the human eye, for that reason also sees objects, larger than we do. Horses' shying is often explained in this way. But the conclusion just mentioned is erroneous. The retinal image is not the perceptual image. It undergoes many transformations within the nervous system itself.
[Y] "Butzenscheiben" are the small circular panes of green glass, used in leaded windows in early days. They are high in the middle (hence the name: "Butze," a protuberance) with a number of concentric circles around the central elevation.—Translator.