SUPPLEMENT 25 



Bordeaux mixture is thus patent ; but it has often been observed to have 

 another and unexpected effect on the sprayed plant, for plants so treated 

 thrive better than control plants, even when the latter are kept free from 

 infection by the fungus. This favourable influence expresses itself in a more 

 vivid green, in the more abundant formation of chlorophyll, and a corre- 

 spondingly increased production of organic substance. More recently, how- 

 ever, this favourable influence has been called in question (comp. SCHANDER, 

 1904 ; EWERT, 1905) ; at all events, it has not been conclusively proved to 

 exist. Should it be really the case, and should the effect be shown to be con- 

 nected with the copper in the Bordeaux mixture, one must assume that only 

 minute traces could enter the leaves of the sprayed plants, for according to 

 HATORI (1899) anything above a 0-00005 per cent, solution of CuSO 4 is injurious 

 to peas, while a 0-000005 per cent, solution is the highest that maize will tolerate 

 without suffering injury. 



89, Bibliography, 1. 27, for ologodynamischen read oligodynamischen. 



90, 1. 24, for Owing to read In accordance with 



91, 1. 5, after consist read for the most part 



1. ii, before aluminium read hydrated, and delete while retaining water, 

 1. 51, after analysis read The water of other rivers, ponds, and lakes has 

 a similar composition ; if, as is often the case, the residue obtained from 

 such after evaporation be greater than that from a river, originating in primi- 

 tive rock, it is especially due to the large amounts of calcium carbonate dis- 

 solved in these waters. Hence it may be readily understood that many aquatics 

 send their roots into the soil, and unless they can obtain nutrients from it, are 

 unable to thrive (POND, 1903). 

 1. 54, for live in read colonize 



92, 1. 3, for unassuming read less exigent 



1. 4, before lichens read Cyanophyceae and 



1.5, before Algae read other 



1. 7, after slowly read or can exist under conditions where growth is slight. 



1. 8, after lichens read and Cyanophyceae 



1. 24, for and amaximum of 4-8per cent, insummer read (compare STOKLASA, 



1905). 



93, 1. 4, for transposition read double decomposition 



I. 13, after sodium, read Absorption and solution are influenced by the 

 mass of the substances acting on each other. 



II. 25-34, for The question of ... by the plant read What we know in 

 a word as ' absorption ' takes place only if certain clays (zeoliths), chalk, or 

 humus are present in the soil ; it does not take place in pure quartz sand. 

 Its importance to the plant lies primarily in the fact that a soil formed by 

 weathering, which is originally poor in plant nutrients, is gradually rendered 

 richer in these substances. Further, the substances so absorbed are, in a large 

 measure, protected by it from being washed out by rain, although they are 

 still capable of being taken up by the plant. 



1. 37, for 36,600 read 36,000 



1. 48, after lichens read and Fungi 



94, 1. 35 P. 96, 1. 9, for For a long time . . . carbon-dioxide in solution. 

 read This is undoubtedly due partly to the fact that the root-hairs, like all 

 other living cells, give off carbonic acid. CZAPEK (1896) thought he had proved 

 that the solvent action of the root was exclusively or in great part due to the 

 excretion of carbonic acid, but PRIANISCHNIKOW (1904) has shown that his 

 arguments are not sound. As a matter of fact, the plant can extract from 

 a soil much more nutrient material than we can with the aid of water hold- 

 ing carbon-dioxide in solution. 



