I40 



Bulletin 244. 



varied between 9.56 per cent, and 16.01 per cent, in the nine 

 varieties grown. The variety, Norbiton Giant, was near both 

 extremes with 9.55 per cent, and 14.88 per cent, of dry matter. 

 Usually about half of this dry matter is sugar, the percentage 

 often varying between three and eight per cent. In nine varieties 

 grown on the University farm during 1904, it varied between 4.23 

 per cent, and 8.99 per cent. ; in this composition Norbiton Giant 



Fig. 51. — Mammoth turnip, A good yicldcr, but having a tendency to pithiness. 



Lower row planted late. 



heads the list, and in another case is found not far from the bottom 

 with 4.77 per cent. It is not the root which gives the greatest total 

 yield, nor yet the richest which is the best to grow, but the one pro- 

 ducing the largest amount of dry matter per acre at the least cost. It is 

 not considered advisable to feed mangels to stock until after Christmas 

 as they appear to contain some ingredient which produces diarrhea in ani- 

 mals, but which disappears when the roots are stored. This substance is 

 thought to be a nitrate, although some authorities suggest that an oxalate 

 or perhaps both may cause the trouble. It is known that nitrates are 



