The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

PHYSIOLOGICAL work on the vertebrate labyrinth has largely consisted of ablation experiments. One of the outstanding difficulties has ever been to produce clean or uncomplicated ablations of the individual receptor organs. MCNALLY and TAIT (1925) selected the frog as a subject for experiment. Refining upon the operative technique hitherto applied to the labyrinth of that animal, they also systematised the methods of examination, so as to make them bear more effectively upon the problem of body and limb posture.' The results obtained seemed to justify the innovations in the experimental procedure.During the past few years we have been able to improve upon our previous operative practice. (The operations have all been carried out by W. J. McN.) The animals operated upon have also been subjected to more extensive test and more careful observation than previously. In the course of our new work we have had occasion not only to repeat all our previous ablations but to follow to further issues many of the results. New ablations, and especially new combinations thereof, have also been greatly used. In this communication, however, we shall restrict ourselves to the description of disabilities that result from the exclusion of one or more of the ampullary receptors of four vertical canals of the labyrinth. Preliminary reports on this subject have already been made by MCNALLY (1931, 1932). TAIT and McNALLY (1929) separated frogs into two components-a leg component and a head-body component-connected by the sciatic nerve. By rapidly tilting the latter component they were able to record corresponding responses of certain muscles of the leg. It is of interest to note that, under the conditions of these experiments, no muscular contraction of any kind occurred in response to mere (slow) angular displacement, however extensive, of the head-body component. An adequate degree of angular acceleration during the movement is essential.1 RADEMAKER (1931) has subsequently adopted similar devices for examination of posture in the mammal.

As is well known, the operation of unilateral labyrinthectomy produces a persistent leaning of the head accompanied by spinal torque. Breuer (1875) once ventured to suggest that damage to the utriculus might be responsible for this effect. Subsequent work by many observers, e.g ., Laudenbach (1899), G. H. Parker (1908, 1909), Benjamins (1920), Maxwell (1920), Manning (1924), McNally and Tait (1925), Versteegh (1927), von Frisch and Stetter (1932), has tended to support this original conjecture. One of the main obstacles to certainty on the subject is the operative difficulty of reaching the utricular macula and of carrying out its uncomplicated ablation. Hitherto the clearest evidence on the matter is that of Versteegh (1927). In the rabbit he succeeded, without damaging other structures, in making a partial severance of the utricular nerve on one side. As a consequence the animal exhibited persistent “Kopfdrehung” towards the side of the operation. If damage to one utriculus causes spinal torque and head twist, the inference is that the utricular maculae, in keeping the head horizontal, are adapted to respond to the field of gravity.

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