1919] 



Hull-Goodspcecl : Ch rysil 



247 



are produced. By the end of December the resting period is prac- 

 tically at an end since shortly thereafter the early spring growing 

 season begins. 



Table 9. — Seasonal ^'ARIATION in Kubber 



ChrysotJuimnus na 



(September 16, 1918, represents the close 

 ber 22, 1918, the close of the resting season.) 



Content of Three Varieties of 

 of the growing season and Decern- 



♦Duplicate analysis. 



It seems probable from the results listed above that during the rest- 

 ing period the resins and other acetone-soluble substances increase in 

 amount while the amount of rubber is diminished. This situation is 

 unexpected in view of the reverse condition described above for 

 Guayule. It is, also, of particular interest when the influence of stor- 

 age of shrub upon resin and rubber content is recalled (cf. p. 224). 

 In the case of storage the per cent of resins was considerably reduced 

 along with a slight reduction in per cent of rubber. Obviously there 



