KEPORT OF THE CHEMIST. 57 



highest amount of nitric acid, but the lowest amount of ammonia. Be- 

 tween sand and chalk there seems to be little difference with regard to 

 their influence upon the production of nitric acid, but the chalk seems 

 to have the strongest influence in the formation of ammonia. If ar- 

 ranged in the order of their relative value, depending upon this latter 

 influence, they would stand, first, chalk, then sand, and garden-soil last j 

 but, if arranged with reference to the total amount of nitrogen trans- 

 formed, the order would be, garden-soil, chalk, sand. In case of a chalk- 

 mixture, the proportion transformed varies from 11 to 53 per cent, of 

 the total organic nitrogen, while for the mixture with garden-soil these 

 limits were 30 to 00 per cent. 



That this power of garden-soil in the transformation of nitrogenous 

 compounds is resident in the humous substances it contains is apparent 

 from the results of Boussingault's experiments; but it is made more evi- 

 dent by the experiments of Simon in his investigation of the function 

 of humus in the soil, from which he concludes that humic acid has the 

 power to appropriate atmospheric nitrogen ; that the absorption of atmos- 

 pheric nitrogen is attended with a liberation of carbonic acid, and that 

 humic acid is insoluble in water free from nitrogen or atmospheric air. 



A curious and interesting fact may be noted in the results obtained 

 by Boussingault. In the mixtures with sand and chalk, raw bone was 

 the only material that yielded any appreciable quantity of nitric acid. 

 The bones seem, therefore, to have a special tendency to the function of 

 nitrification ; a theory supported by the fact that M. Herve Magnon 

 found by analysis large quantities of nitric acid in the drain age- waters 

 of the ossuaries of the catacombs of Paris. 



With regard to ammonia, Houzeau has discovered a peculiar quality : 

 that when a solution in water is allowed to stand for some time, it com- 

 pletely disappears from the solution. It is well known that it is always 

 present iu rain-water; but found in comparatively small quantities in 

 spring and river water, a fact which has always been considered due to 

 absorption by the soil ; but M. Houzeau found that it disappeared from 

 solutions under conditions leading to the conclusion that light has in 

 some way an influence in bringing about this result. 



While the methods involved in the appropriation and assimilation of 

 atmospheric nitrogen were being made, Gorup-Besanez and Will have 

 developed some important facts in connection with the utilization of 

 combined nitrogen in the interior of the plant. Thus they have suc- 

 ceeded in separating from the seeds of Cannabis saliva, (hemp,) and 

 Linum usitatisimum, (linseed,) and some kinds of malt, a ferment capa- 

 ble of acting upon fibrin and albumin in a manner similar to pepsin. 

 It is snow-white and pulverulent, and retains its activity for weeks when 

 kept in well-closed vessels. It changes starch-paste into* sugar within 

 an hour, and acts rapidly upon fibrine-forming peptones. They also 

 found the same ferment in the sap of different species of Nepenthes, and 

 its action upon animal substances so decided that it has been declared 

 to be a vegetable solution of pepsin. 



Passing from the absorption of nitrogen and the formation of nitrog- 

 enous compounds, we come to the formation of carbohydrates. Liebig 

 and Eochleder believed that the organic acids (oxalic, tartaric, &c.) 

 form the transition links between atmospheric carbonic acid and the 

 carbohydrates in the economy of plant- growth, while Davy, Sachs, and 

 others hold that the transformation is direct, with no intermediate steps. 

 Baeyer subsequently advanced the theory that when sunlight falls upon 

 chlorophyll in plants well supplied with carbonic acid, the latter seems 



