Reserve Material of Plants. 197 



3. The reserve starch is least during active growth and great- 

 est just after the fall of the leaves. 



4. The amount of stored material is most variable in the bark, 

 and least variable in the wood and pith. 



5. Reserve material appears most abundantly in the oldest 

 tissues and those which are most strongly lignified, least abun- 

 dantly in the tissues where the vitality is greatest. 



6. The storage of the carbohydrate is first in the old and 

 lignified cells, and last in the most active structure. 



7. The solution of the stored starch is first in the active paren- 

 chyma cells, and last in the permanent tissues. 



8. There is a gradual solution of the stored starch during the 

 period of rest. 



9. Leaves normally contain an abundance of starch during 

 the period of their greatest activity, but as they ripen the starch 

 is replaced by oil. 



In 1871, Nobbe and Schroeder demonstrated the influence 

 which may be exerted upon this distribution by an abnormal 

 food supply. Their experiments with buckwheat, to determine 

 the specific value of chlorine and potash, were found to have an 

 important bearing upon the products of assimilation. The potash, 

 as is now so well known to be the case, was found to be essential 

 in the first instance to the formation of the reserve material, 

 while the chlorine was observed to bear a most important relation 

 to its final distribution. Withholding the chlorine, the starch accu- 

 mulated in the tissues where formed, so that the bark and leaves 

 became abnormally charged with it, particularly in the young 

 growth. At the same time there was marked atrophy, together 

 with high discoloration of all the growing parts, showing a failure 

 of proper nutrition and, therefore, of distribution of the digested 

 material. Restoration of chlorine to the food-supply gradually 

 effected distribution of the starch and restoration of the normal 

 growth. This then shows what may be produced by artificial 

 treatment, and clearly demonstrates the dependence of the physio- 

 logical activity upon the presence of special elements and com- 

 pounds. It also leads us to infer that similar abnormal condi- 

 tions may develop whenever the plant is deprived of these special 

 elements of food under conditions of ordinary growth. 



Acting upon these suggestions, Dr. Goessmann and I have, for 



