Periodical Literature. lo^ 



the atmosphere, as the burning of all carbohydrates, burning of 

 coal, escaping of artificial illuminating gas, producing of gas in 

 the bee hive method of coking, escaping of certain sorts of nat- 

 ural gas, and probably other processes. So far as known, there 

 is in nature no special absorbent for ethylene, also no cycle for 

 the gas as there is' for carbon dioxide and oxygen. Having no 

 estimate of the total additions to the atmosphere from the sources 

 indicated above, one cannot calculate whether accumulation up 

 to the danger point is likely to occur. One factor that favors 

 the effectiveness of the oxides of sulphur as plant poisons in the 

 open as against heavy hydrocarbons is their great solubility- in 

 the plant cell which would lead to their accumulation even under 

 great variation in atmospheric concentration, whereas the heavy 

 hydrocarbons would accumulate to a far less degree and varia- 

 tions in concentration greatly reduce their injurious effects. 



C. D. H. 



The Botanical Gazette, May, 1913, pp. 337-371. 



SOIL, WATER AND CLIMATE. 



Goddard is one of the latest investiga- 

 Soil tors to attack the much debated question of 



Fungi. the power of non-mycorhizal fungi grow- 



ing freely in the soil to fix free nitrogen. 

 Eighteen species were isolated from samples of garden soil and 

 grown on culture plates. Seven of them were the same as 

 those found in forest soil by investigators in Holland. It ap- 

 pears that, unlike bacteria, these fungi are rather uniformly dis- 

 tributed in the soil, at least to a depth of about six inches. Most 

 of the fungi studied were taken from three plots; one of which 

 was untilled and unfertilized, one well tilled but unfertilized, the 

 other both well tilled and well fertilized with stable manure. 

 The fungous flora, however, did not diflfer materially in species 

 or abundance in the three cases. The most abundant in all of 

 the plots were members of the genera Miicor and Fusarium. 

 The author made tests of some 14 species and none of them 

 showed any power of assimilating free nitrogen when grown 

 in nitrogen-free media. In looking over the literature of tlie 

 problem, however, one finds more evidence that soil fungi do 



