FROM THE AIR BY THE LEGUMINOSiE 33 



nitrogen. In support of this Jamieson lays stress on the fact 

 that the upholders of bacterial theories have never been able 

 to prove the presence of bacteria in the nodules ; as a matter 

 of fact, no observer who has paid attention to this question 

 has found anything more than fungi, fungoid hypha?, 

 sporangia or spores. 



The fact that the Leguminosce are more subject to the 

 attacks of fungi causes Jamieson no surprise. Greedy for 

 nitrogen, the fungi are more likely to be attracted by the 

 Leguminos^, whose roots afford nourishment rich in that 

 element. The nodules are only formed to engulf the fungus, 

 to render it inactive, and to heal the wound. 



The author further proves that fungi, being devoid of 

 chlorophyll, are in all probability unable to absorb nitrogen, 

 and since the bacteria themselves are under the same dis- 

 advantage, we are justified in concluding that they too are 

 unable to perform this function. 



In proof of this, Jamieson quotes the case of turnip fields 

 ravaged by a particular fungus, and takes as his authority 

 Professor Trail, of Aberdeen University, who, after having 

 made a special study of pathogenic formations, asserts 

 that the action of a fungus is sufficient not only to cause 

 the formation of tubercles of this kind, but further to excite 

 in the plant a reaction involving a certain richness in com- 

 position in the part attacked. 



According to Jamieson, therefore, the formation of 

 nodules is nothing remarkable; it is merely one case among 

 a number of analogous ones. 



Another fact which the author brings forward in support 

 of his thesis is the capacity of all plants, except those devoid 

 of green matter, to fix atmospheric nitrogen by means of 

 certain aerial organs. Alg^ which are composed of simple 

 loose green cells fix atmospheric nitrogen. Franck's ex- 

 periments show that 25 to 36 per cent, of the total nitrogen 

 content of these plants is absorbed by the cells containing 

 green matter. 



3 



