difference in the ability of fungi to endure alcohol, as is shown among those 

 which still introduce an actual alcohol fermentation. For Saccharomycetes, 12 

 per cent, of the weight is the limit of growth ; 14 per cent, the limit of fermen- 

 tation. In Mucor racemosus, which lives on sugar without free oxygen, the 

 limit of growth and of fermentation lies between 4}^ and 5>^ per cent, alco- 

 hol ; Mucor stolonifer, on the other hand, no longer grows and can not be- 

 gin fermentation with 1.5 per cent, alcohol. It should be concluded from 

 these results that under the same external conditions even phanerogams 

 succeed in forming alcohol of very different percentages and endure it in 

 dift'erent amounts. 



Later Muntz^ speaks very generally of alcohol as one of the decomposi- 

 tion products of organic substances formed on the surface of the earth as 

 well as in the soil and in the depths of the ocean and distributed in the at- 

 mosphere according to the laws of the tension of gases. 



It can not be surprising that organic acids, among others acetic acid, 

 occur in the fermentation of alcohol. It is very probable that the accumu- 

 lation of such acids must ultimately act as a poison upon the organisms and 

 that in roots, which are entirely or almost entirely cut oft' from atmospheric 

 oxygen, there will begin a gradual dying back. 



When trees have been planted too deep and the roots need an abundance 

 of air, perhaps more than the top part of the plant, the lack of oxygen will 

 be felt more quickly the greater the power of the soil to hold water and the 

 more the parts are cut off by water-. Water near the living roots 

 becomes more and more a source of danger for the larger, healthy roots 

 and for the sunken bases of the trees, since the water becomes more and more 

 charged with carbon dioxid. If healthy plants are set in water containing 

 much carbon dioxid they begin to wilt and the leaves begin to die back^. 

 Kosaroff's* studies on the absorption of water in insufficiently drained 

 soils, i. e. those poor in oxygen a..d rich in rarbon dioxid, are especial- 

 ly interesting. The water absorption and transpiration were proved to 

 be repressed by the carbon dioxid. Plants whose roots remained in an at- 

 mosphere rich in carbon dioxid lost their turgidity immediately and be- 

 came limp ; when kept there longer they disintegrated. In experiments in an 

 hydrogen atmosphere wdiere, therefore, only the lack of oxygen becomes de- 

 pressing, it was shown that this circumstance does not act in any way as in- 

 juriously as an excess of carbon dioxid. 



Therefore, in the roots of trees lying too deep, death by poison begins 

 by attacking first the tender organs, later the older ramifications of the roots. 

 At the same time the putrid products of decomposition make the whole soil 

 unfit for the growth of plants. Bohm^"^ cites an exami)le in the dying 



1 From Compt. rend. Vol. I.XXXXII, p. 499. cit. in Biedermann's Contralbl. ISSl. 

 p. 709. 



2 Mayer, Agrikulturchemie, 5th Edition, 1901, Vol. I, p. 116. 



3 Wolf. W., Tageblatt der Naturforscher-Versammlung- zu Leipzig, 18.-, p. -"■'. 

 i Kosaroff, Einfluss verscliiedener ausserer Faktoren auf die Wasseraufnahnie 



der Pflanzen. Dissert. Leipzig, 1897, cit. Naturw. Rundschau, 1S97. No. 47. 



5 Bohm, J., Ueber die Ursache des Absterbens der Gotterbaume und uber die 

 Methode der Neubepflanzung der Ringstrasse in Wein. Faesy & Frick. 



