no On Protagon 



difference in the phosphorus percentage is only 0*03 per cent, more than in 

 the samples of Lesem and Gies, the variation in these being 0"94 per cent, 

 to 1'34 per cent. 



Gies further states (in his recent paper on Paranucleo - Protagon, 

 American Journal of Physiology, xx. 2, p. 379), referring to our results : 

 " When the phosphorus contents of their protagon products were lowered by 

 recrystallisation to the percentage amount that appeared to them to be 

 about right, they arbitrarily discontinued in each case the recrystallisation 

 process, in spite of the fact that repetition of it promised to decrease further 

 the proportionate contents of phosphorus." I have looked in vain through 

 our paper for any statement which could warrant this wanton suggestion. 



PAPERS REFERRED TO. 



Baumstark, Zeitschrift fur physiologische Chemie, vol. ix., 1885, p. 145. 



Cramer, Journal of Physiology, vol. xxxi., 1904, p. 31. 



Gamgee, Text-Book of Physiological Chemistry, London, 1880, p. 441. 



Gamgee and Blankenhorn, Zeitschrift flir physiologische Chemie, vol. iii., 

 1879, p. 260. 



GuLEWiTSCH, quoted from Noll. 



KosSEL and Freytag, Zeitschrift fiir physiologische Chemie, vol. xvii., 1893, 

 p. 431. 



Lesem and Gies, American Journal of Physiology, vol. viii., 1902, p. 183. 



Liebreich, Liebig's Annalen der Chemie und Pharmazie, vol. cxxxiv., 1865, 

 p. 29. 



Lochhead and Cramer, Biochemical Journal, vol. ii., 1907, p. 350. 



Noll, Zeitschrift fiir physiologische Chemie, vol. xxvii., 1899, p. 370. 



PosNBR and Gies, Journal of Biological Chemistry, vol. i., 1905, p. 59. 



Rosenheim and Tebb, Journal of Physiology, vol. xxxvi., 1907, p. 1. 



RUPPBL, Zeitschrift fiir Biologie, vol. xxxi., 1895, p. 86. 



Thudichum, Die chemische Konstitution des Gehirns, Tubingen, 1902. 



Wilson and Cramer, Seventh International Congress of Pliysiology, Heidelberg, 

 1907. 



WoRNER and Thierfelder, Zeitschrift fiir physiologische Chemie, vol. xxx., 

 1900, p. 542. 



The expenses of this research have been defrayed by a grant from the Moray 

 Fund of the University of Edinburgh. 



