205 



The present work was carried out by me in the Physiological In- 

 stitute of the Royal University of Naples. 



I am greatly indebted to Prof. F. Bottazzi, Director of the said In- 

 stitute, for having kindly placed the laboratories of the Institute at my 

 disposai. 



Finito di stampare il 30 marzo 1918. 



