ABSORPTION OF ASH-CONSTITUENTS 



IOI 



Toxins of some agricultural soils are organic in nature, as is indicated by the 

 following experiment. 1 Water extract of a soil that had become alfalfa-sick 



Fig. 65. — Vicia faba (Windsor bean) plants grown in water extract of bog-soil and in bog 

 water. 1, extract; 2, bog water; 4, bog water neutralized with calcium carbonate; 5, bog 

 water treated with carbon-black and filtered. (After Dachnowski.) 



was toxic to this plant, but if the soil was brought to a red heat before making 

 the extract the latter was not toxic. Water extracts of other soils, which had 



gaz. 39: 348-355. 1905.) It appeared also that this toxicity (for the alga used) was surely 

 not directly related to acidity, the degree of acidity being measured with phenolphthalein 

 as indicator. It is interesting to note that this first step toward an analysis of the bog-water 

 problem occurred at almost exactly the same time as the general problem of toxic substances 

 in arable soils was opened up (in its modern sense) by Whitney and Cameron (1904) [see 

 note 1, p. 99] and by Belford and Pickering (1903) [see note j, p. 99]. The three lines of 

 work were entirely independent. Transeau also (Transeau, E. N., On the development 

 of palisade tissue and resinous deposits in leaves. Science, n. s. 19: 866-867. 1914) had 

 shown that bog water is toxic, to Rumex at least, before the excellent studies of Dachnow- 

 ski (cited here in text), and those of Rigg were published. (Rigg, G. B., The effect of some 

 Puget Sound bog waters on the root hairs of Tradescantia. Bot. Gaz. 55: 314-326. 1913. 

 Idem, The toxicity of bog water. Amer. jour. bot. 3: 436-437. 1916. Idem, A summary 

 of bog theories. Plant world 10: 310-325. 1916.) It seems probable that microorganisms 

 and lack of oxygen have to do with the production of these bog toxins. — Ed. 



1 Pouget, I., and Chouchak, D., Sur la fatigue des terres. Compt. rend. Paris 145: 1200-1203. 1907. 



