A I) H E S T (') X DEL P R O I- . | O H X S T ( ) X 



Dear Professor Tello: 



It would give me great pleasure to contribute an article to thc memo- 

 rial volume in honor of Professor Ramón y Cajal. Howevcr, owing to 

 my absence from honie, your letter inviting a contribution clid not reach 

 me until a few days before the date set for receiving such contributions. 



1 he work upon which I am at present engaged is in a field in which 

 Professor Ramón y Cajal has made notable contributions, namely the 

 morphology and evolution of the cerebral hemispheres. His example ot 

 scientific industry and enterprise, his accuracy of observation and clear- 

 ness in interpretation have been a constant source of inspiration to me. 



It is fitting to mention some of the problems which the writer is try- 

 ing to solve, since the pursuit of these problems has been largely due to 

 the early influence of the brilliant researches of Professor Ramón y Ca- 

 jal. The origin of the medial and lateral parts of the caudate nucleus 

 and the significance of the stria terminalis; the phylogenetic origin and 

 signiticance of the diagonal band of Broca and the anterior perfórate spa- 

 ce; the source and functional relations of the parts of the lobus pyrihir- 

 mis; the history of the primary nuclei of the amygdaloid complex and 

 the source and function of the later additions of new nuclei; the primiti- 

 ve segmental relations of the fore brain in the vertébrate head, the evolu- 

 tion of the hippocampus and general pallium and the general form-evo- 

 lution of the cerebral hemispheres; the factors of environment and habits 

 which have determined the functional relationships and the morphologi- 

 cal development of the parts of the fore brain. 



Since it is not possible undcr present circumstances to put an\' part 

 of this into suitable form for publication in the memorial volume, I beg 

 loave to express in this way the highest esteem for Professor Ramón y 

 Cajal, my appreciation of his great contributions to science, and my feel- 

 ing of indebtedness to his work. 



J. H. JolINSTOX. 

 Scripps Institution for I^iological Research, La jolla, California, Marih .\ \i.)22. 



