THE CORTICAL MOTOR CENTRES IN LOWER 



MAMMALS. 



By C. L. Herrick. 

 With Plate XIV. 



Two recent papers relating to the excitable zone of the 

 cortex of the opossum recall an extended series of experiments 

 made by the writer prior to 1 892 but which have been pub- 

 lished only in part and seem to have failed to reach the public 

 for whom they were intended, 



R. H. Cunningham^ remarks : " To be sure, the micro- 

 scopical as well as the macroscopical anatomy of the opos- 

 sum brain has been minutely described by Herrick, who 

 regards the precrucial lobe as typically motor in its micro- 

 scopical structure and the parietal and occipital portions as 

 composed of motor and other nerve cells, but this writer 

 does not state whether this view has been corroborated 

 by a physiological investigation of the cortex with the 

 electrical current." The writer must admit that he has often 

 failed to take the usual steps to bring his papers to the attention 

 of fellow workers (though reference is made to experiments in 

 the paper quoted) and it may be that the fact that Professor 

 Cunningham as also Professor Ziehen^ overlook the observations 

 referred to, is due to in part to this negligence. That part of 

 the series not heretofore published has been withheld in the 

 hope that an opportunity might yet arise for the completion of 

 the contemplated series. The preliminary account appeared in the 

 paper prepared jointly by Professor VV. G. Tight and the writer 

 and printed in the Bulletin of the Laboratories of Denison Univer- 



* The Cortical Motor Centres of the Opossum. Joiirn. Physiology, XXII, 4. 



* Ueber die motorishe Rindenregion von Didelphys. Centralblatt fiir Phys- 

 iologies XI, 15. 



