212 THE JOURNAL OF INDIAN BOTANY. 



Senecio Lawsoni Gamble sp. nov. 1. c. p. 342, allied to S. lavandulacfolius 

 DC, but with small leaves uniformly borne by the etem, few flowered 

 corymbs and many nerved ligules, Dist. Nilgiris : Avalanche to Sisparah. 



Physiology 



Beckley, V. A The preparation and fractionation of Humic 

 acid ; and the formation of Humus. Jour. Agric. Science, XI, 1st 

 January, 1921, pp. 66 & 69. 



In the first of these papers the author describes experiments which go to 

 show that humic acid obtained by ashing the humus obtained from an 

 alkaline extract of soil by an acid or by boiling sugar with acid is a mixture 

 of two acids, separable by pyridine ; one probably tri-basic and the other 

 terra-basic ; and not one body as previously supposed. 



In the second he shows that carbohydrates when acted on by acids, 

 whether mineral or amino, produce hydroxymethyl-furfural, (a ring com- 

 pound consisting of an oxygen atom linked to 4 carbons, to which are 

 attached CH2 OH ; CH ; and CHO respectively) and that this condenses 

 to humus. This is the process whether the action takes place in the 

 laboratory or the held, and whether from sugar, celluluse or straw. No 

 evidence could be obtained that hydroxymethyl-furfural was produced 

 during the decomposition of cellulose by Spirochseta cytophaga. 



P. F. F. 



Harrison, W. H. Carbon dioxide in relation to rice soils. Memoirs 

 of the Department of Agriculture in India. Chemical Series V. 

 8th November, 1920. 



In a previous paper the author and Subramanya Aiyar showed that the 

 gasses of paddy soil are mainly methane and nitrogen, while carbon-dioxide 

 and hydrogen occur only in small quantities. But in ordinary decomposi- 

 tion of organic matter under anerobic conditions, such as presumably obtain 

 in paddy soil, the opposite is the case, there is little nitrogen and much 

 hydrogen and carbon-dioxide. From the experiments described in this paper 

 the author concludes that this difference is due not to the fermentation 

 being of a different type, but to secondary chemical changes where by the 

 hydrogen and carbon-dioxide produced combine to form organic matter 

 and methane. The result of this is that there is less hydrogen available 

 to absorbe oxygen, thus increasing the amount of the latter available 

 for eeration of the roots. Another advantage to the plant is the removal 

 of the carbon-dioxide. The methane is also of use since it increases the 

 oxygen supply by the action of the surface film, as shown in a previous 

 paper. The organic matter so formed will also be decomposed in like 

 manner, with fresh evolution of methane and nitrogen. In this way com- 

 paratively large quantities of nitrogen are set free, and there is no need 

 to postulate the action of specific bacteria, 



P. F. F. 



