292 Journal of Comparative Neurology. 



logical' or ♦metaphysical.' The old 'center' is a sort of 

 homunculus, a mysterious pigmy who acts his part as a little 

 man would, accumulates images and energies and discharges 

 them, sends them along the wires of fiber-paths to his superiors 

 and inferiors who discharge again on others. Such action is 

 decidedly more anthropomorphic-electrical than physiological. 



The plan offered here is one of physiological mechanisms, 

 leaving open the ultimate question what the * discharge ' and 

 the life-process of the individual neurone really is, but search- 

 ing patiently for details of the relations of neurones and of 

 the parts of neurones to one another. It turns against the 

 tiresome habit of riding every detail-discovery to death by try- 

 ing to explain through it the whole unknown and is more seri- 

 ously bent on a large plan which shall not come into conflict 

 with any of the possibiUties of detail. It takes its base in the 

 oldest and best-known and best-knowable, the segmental ner- 

 vous system, and proceeds to the superstructures, the cerebel- 

 lum, midbrain, thalamus and cerebrum, on this basis. At the 

 same time it remembers certain general concepts of biology as 

 not altogether out of place where general methods of reasoning 

 are in question. 



The medical literature shows a great deal of the stand- 

 point of Cartesian localization left ; however modified and di- 

 luted, it is Cartesian in principle. Nobody would, of course, 

 search the pineal gland for the spring of all action, the * soul ' ; 

 but this same soul is, though split up a little, seated in the cen- 

 ters. A truly biological spirit trained in comparative anatomy 

 and physiology would hardly embrace this attitude except per- 

 haps for the carelessness with which we always use old-fash- " 

 ioned ways of speaking. To these consistent or casual ' Car- 

 tesians ' I would like to recall the famous statement of Spinoza 

 which may lead the ' psychologically ' inclined students to- 

 wards a more modern biological concept : Et enim quid cor- 

 pus possit, nemo hucusque determinavit, hoc est, neminem 

 hucusque experientia docuit, quid corpus ex solis legibus nat- 

 urae, quatenus corporea tantum consideratur, possit agere, et 

 quid non possit, nisi a mente determinetur. 



