SUPPLEMENT 



27 



From the fact that CaSO 4 is not injurious, while CaC0 3 rapidly brings 

 about death, it follows that it is not the Ca-ion that acts poisonously ; it 

 must be due, on the other hand, rather to a secondary effect of the lime, a view 

 supported by the investigations of FLICHE and GRANDEAU (1873). These 

 investigators analysed the ash of trees which had been grown in normal soil, 

 and compared it with the ash of other specimens which had passed a miser- 

 able existence in a soil rich in lime. The result of this comparison was to show 

 that the ash of those grown in a siliceous soil contained 40-45 per cent, of 

 lime, while in those from a lime soil the percentage rose to 56-75 per cent. ; 

 at the same time, the absorption of potassium was much reduced (from 16-22 

 per cent, down to 4-6 per cent.). It is conceivable that the diminution in the 

 absorption of potassium was due simply to the fact that the calcium carbonate 

 rapidly neutralized the acid secretions of the root, and so interfered with its 

 disintegrating action on intractable rock materials. It also appears probable 

 that calciphobous plants have a considerable need for potassium. ENGLER 

 (1901) says that the calciphobous chestnut can thrive on sandstone and marl 

 rich in lime if these be at the same time rich in potassium. In addition to 

 a diminution in potassium there is a deficiency in magnesium and iron. In 

 support of this view one may cite the fact that calciphobous plants become 

 chlorotic on lime soils (Roux, 1900), and that this chlorosis (according to 

 a verbal statement by Professor STAHL) can be rectified by spraying with 

 a solution containing iron. 



1- 36, for calciphobous read calciphilous 



100, 1. 34, before SCHIMPER read SOLMS (1905), 



11. 50-2, for and at the same time ... in the soil read and thus draw 

 attention to another aspect in which the minerals present in the soil are of 

 fundamental importance. 



101, 11. g-i2,for EBERMAYER ... of the ash read According to a table com- 

 piled by CZAPEK (Biochemie, II, p. 842) a hectare of field crops or woodland 

 abstracts from 50 to 350 Kg. of ash annually from the soil, e. g. 



Pine Wheat Beech Potato Clover 



49 Kg. 196 Kg. 210 Kg. 2 17 Kg. 343 K g- 



11. 19-20, for and even . . . applications read by the use of different media, 

 learnt from experience, which are easily explicable theoretically, or, better 

 still, the exhaustion may be prevented by the employment of these media at 

 the appropriate time. 



11. 43-4, for nitric acid read nitrogen 



P. 103, 1. 7, after our attention, read We have to consider not only in what 

 form and by what organs the carbon is absorbed from the environment, but 

 also to show how it is combined after entering the plant. To this process of 

 transmutation of a nutrient into plant substance we give the name of ' assimila- 

 tion ', and describe as ' assimilata ' the first formed products. The reason 

 why, in treating of the materials of the ash, we have not employed this ter- 

 minology is because we know so little as to the changes which take place, and 

 because what little we do know can be discussed more appropriately elsewhere 

 (Lecture XI). 



11. 34-51, delete [Following PFEFFER ... in so doing.] 



104, 1. 23, after water read (HANSEN, 1899) 



1. 52, for forms a means of measuring read furnishes a measure of 



105, 11. 17-19, for [If POLLACCI'S criticism . . . worthless !] read (As to the 

 method of working this apparatus see SCHMIDT (1902). A criticism, and, 



