Localisation of function in the lemur’s brain

The brain of the Lemur, the lowest of the ape-like animals, does not appear to have been subjected previously to a thorough examination. Page May and Elliott Smith brought a brief communication on the subject before the Cambridge Meeting of the British Association in 1904. Their experiments were apparently limited to stimulation of the cerebral cortex, and they have never published a full account of their work. Brodmann has worked out some of the histological details of the structure of the cortex cerebri, and Max Volsch has performed a stimulation experiment upon one Lemur. The work of these investigators will be referred to again in the course of this paper. Our own investigation has in the main dealt with the motor centres, and the experimental methods adopted have been the usual ones of stimulation and extirpation. In animals so low in the scale, stimulation is to be regarded as the more decisive of the two methods for the purpose of localisation. The extirpation experiments have, however, confirmed the results of stimulation, and in these experiments the course of the resulting degeneration was followed by histological examination of the brain and spinal cord. The results, moreover, agree remarkably closely with those obtained by a study of the histological structure of the various regions of the cortex cerebri.