THE ENERGY OF THE LIVING PROTOPLASM. 



I 7 I 



If we add, for example, to the mixture mentioned, sodium 

 carbonate, or boil the mixture with addition of calcium car- 

 bonate, no trace of the rancid smell will be noticed after addition 

 of a mineral acid ; the absorbed oxygen is here too quickly used 

 up for oxidation. 



Another process, hitherto unexplained, is the easy reduction 

 of nitrates to ammonia in the formation of proteids (cf. Chap. V). 

 As there exists no nascent hydrogen in the living cells, I had 

 long entertained the view that glucose under the katalytic 

 influence of the living protoplasm would be the reducing agent, 

 and recently have succeeded in imitating this reduction by 

 means of platinum-black. I heated in my first experiment a 

 solution of 3 g. potassium nitrate and 10 g. glucose, in 300 g. 

 water with no g. platinum-black for 6 hours to Co-70 0 and found 

 that 45.6 % of the nitrogen of the nitrate had been converted 

 into ammonia. This reduction can even succeed at the 

 ordinary temperature. If 50 cc. of a mixture of a 5-10 % glucose 

 solution with 1-2 % calcium nitrate and 10 g. platinum-black is 

 left to stand for 4-5 days in a closed flask, we observe upon 

 supersaturation with caustic lye a strong ammoniacal odour, while 

 in a control experiment without the platinum no trace is obser- 

 vable. ( "' If we modify the experiment by increasing the amount 

 of the nitrate to three times that of the sugar, we find on heating 

 that the acid reaction generated at first soon diminishes and 

 finally gives way to an alkaline one, and then the ammonia pre- 

 viously formed becomes very perceptible by its odour. (,) The 

 platinum-black imparts to the hydrogen atoms of the glucose 

 increased motions, thereby loosening the existing affinities, and 

 awakening others, whereby a reduction of the nitrate is caused, 

 i.e., an exchange of oxygen and hydrogen between the nitrate and 

 the sugar. 



In a similar way, chlorates are reduced to chlorides; 

 sulphates however resist its action and require evidently more 



(1) Other control experiments were also made, which proved beyond any doubt 

 that only the platinum-black itself and not any oxidation product or bacterial action 

 was the cause of the formation of ammonia. 



(2) If the mixture is rendered alkaline before the platinum-black is added, no 

 ammonia will be produced, a result which finds its explanation in what has been 

 mentioned above. 



